Debt and Capital Lease Obligations - Senior Notes (Details)
Apr. 30, 2018
USD ($)
exception
Jul. 01, 2014
USD ($)
Debt Instrument [Line Items]    
Original Principal Amount $ 1,094,276,000  
Senior Notes [Member] | Senior Unsecured Notes Due July 2022 [Member]    
Debt Instrument [Line Items]    
Original Principal Amount   $ 250,000,000
Interest rate on notes (in hundredths)   7.25%
Effective interest rate   7.80%
Number of exceptions for limitations | exception 2  
Restricted payment basket amount $ 375,000,000.0  
Leverage ratio 2.50  
Restrictions on payment of dividends, amount free from restriction $ 183,500,000  
Trigger amount under indenture   $ 25,000,000
Line of Credit [Member] | Revolving Credit Facility [Member]    
Debt Instrument [Line Items]    
Restrictions on payment of dividends, amount free from restriction $ 64,700,000