Quarterly report pursuant to Section 13 or 15(d)

Long-Term Debt - Components of Long-term Debt (Details)

v3.8.0.1
Long-Term Debt - Components of Long-term Debt (Details) - USD ($)
 3 Months Ended 6 Months Ended
Mar. 31, 2018
Mar. 31, 2018
Dec. 30, 2017
Dec. 14, 2017
Sep. 30, 2017
Mar. 25, 2017
Nov. 09, 2015
Debt Instrument [Line Items]              
Total $ 691,104,000 $ 691,104,000     $ 395,653,000 $ 496,244,000  
Less current portion (20,000) (20,000)     (375,000) (374,000)  
Long-term portion 691,084,000 691,084,000     395,278,000 495,870,000  
Senior notes              
Debt Instrument [Line Items]              
Unamortized debt issuance costs (9,053,000) (9,053,000)     (4,840,000) (5,237,000)  
Total 690,947,000 690,947,000     395,160,000 394,763,000  
Senior notes | Senior notes, interest at 6.125%, payable semi-annually, principal due November 2023              
Debt Instrument [Line Items]              
Notes $ 400,000,000 $ 400,000,000     400,000,000 400,000,000 $ 400,000,000
Debt instrument maturity period   Nov. 01, 2023          
Debt instrument interest rate stated, percentage 6.125% 6.125%         6.125%
Senior notes | Senior notes, interest at 5.125%, payable semi-annually, principal due February 2028              
Debt Instrument [Line Items]              
Notes $ 300,000,000 $ 300,000,000   $ 300,000,000.0 0 0  
Total $ 295,300,000 $ 295,300,000          
Debt instrument maturity period   Feb. 01, 2028          
Debt instrument interest rate stated, percentage 5.125% 5.125% 5.125% 5.125%      
Asset-based revolving credit facility, interest at LIBOR plus a margin of 1.25% to 1.50% or Base Rate plus a margin of 0.25% to 0.50%, final maturity April 2021              
Debt Instrument [Line Items]              
Total $ 0 $ 0     0 101,000,000  
Debt instrument maturity period   Apr. 01, 2021          
Asset-based revolving credit facility, interest at LIBOR plus a margin of 1.25% to 1.50% or Base Rate plus a margin of 0.25% to 0.50%, final maturity April 2021 | Base rate borrowings              
Debt Instrument [Line Items]              
Applicable interest margin rate on the credit facility 0.25%            
Asset-based revolving credit facility, interest at LIBOR plus a margin of 1.25% to 1.50% or Base Rate plus a margin of 0.25% to 0.50%, final maturity April 2021 | LIBOR-based borrowings              
Debt Instrument [Line Items]              
Applicable interest margin rate on the credit facility 1.25%            
Asset-based revolving credit facility, interest at LIBOR plus a margin of 1.25% to 1.50% or Base Rate plus a margin of 0.25% to 0.50%, final maturity April 2021 | Minimum | Base rate borrowings              
Debt Instrument [Line Items]              
Applicable interest margin rate on the credit facility   0.25%          
Asset-based revolving credit facility, interest at LIBOR plus a margin of 1.25% to 1.50% or Base Rate plus a margin of 0.25% to 0.50%, final maturity April 2021 | Minimum | LIBOR-based borrowings              
Debt Instrument [Line Items]              
Applicable interest margin rate on the credit facility   1.25%          
Asset-based revolving credit facility, interest at LIBOR plus a margin of 1.25% to 1.50% or Base Rate plus a margin of 0.25% to 0.50%, final maturity April 2021 | Maximum | Base rate borrowings              
Debt Instrument [Line Items]              
Applicable interest margin rate on the credit facility   0.75%          
Asset-based revolving credit facility, interest at LIBOR plus a margin of 1.25% to 1.50% or Base Rate plus a margin of 0.25% to 0.50%, final maturity April 2021 | Maximum | LIBOR-based borrowings              
Debt Instrument [Line Items]              
Applicable interest margin rate on the credit facility   1.50%          
Other notes payable              
Debt Instrument [Line Items]              
Total $ 157,000 $ 157,000     $ 493,000 $ 481,000