Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Narrative (Details)

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Fair Value Measurements - Narrative (Details) - USD ($)
Mar. 31, 2018
Dec. 30, 2017
Dec. 14, 2017
Sep. 30, 2017
Mar. 25, 2017
Nov. 30, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Carrying value of senior subordinated notes $ 691,104,000     $ 395,653,000 $ 496,244,000  
Senior notes            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Carrying value of senior subordinated notes $ 690,947,000     395,160,000 394,763,000  
Senior notes | Senior notes, interest at 5.125%, payable semi-annually, principal due February 2028            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Debt, aggregate principal amount   $ 300,000,000        
Debt instrument interest rate stated, percentage 5.125% 5.125% 5.125%      
Estimated fair value of senior notes $ 285,400,000          
Carrying value of senior subordinated notes 295,300,000          
Senior notes | 6.125% senior notes due in November 2023            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Debt, aggregate principal amount           $ 400,000,000
Debt instrument interest rate stated, percentage           6.125%
Estimated fair value of senior notes 419,000,000     427,900,000 422,400,000  
Carrying value of senior subordinated notes $ 395,600,000     $ 395,200,000 $ 394,800,000