Debt - Senior Credit Facility (Details) $ in Thousands, AUD in Millions	Aug. 27, 2014 AUD	Sep. 30, 2015 USD ($)	Dec. 31, 2014 USD ($)	Aug. 27, 2014 USD ($)
Line of Credit Facility [Line Items]
Term loan		$ 293,250	$ 295,500
Revolver		$ 490,000	$ 70,000
Weighted average interest rate		2.80%
Term Loan
Line of Credit Facility [Line Items]
Term loan		$ 293,250
Letter of Credit
Line of Credit Facility [Line Items]
Long-term debt		58,100
Additional Revolver
Line of Credit Facility [Line Items]
Borrowing capacity increase		151,900
Term Loan | Credit Facility Term Loan
Line of Credit Facility [Line Items]
Face amount				$ 296,300
Term Loan | London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Basis spread on variable rate	2.50%
Term Loan | London Interbank Offered Rate (LIBOR) | Minimum
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.75%
Revolver
Line of Credit Facility [Line Items]
Revolver		$ 490,000
Revolver | Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity				$ 700,000
Revolver | London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Basis spread on variable rate	2.25%
Revolver | London Interbank Offered Rate (LIBOR) | Minimum
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.00%
Australian LC Facility | Letter of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity | AUD	AUD 225.0
Amount outstanding on letters of credit | AUD	AUD 215.0
Credit Agreement
Line of Credit Facility [Line Items]
Total leverage ratio	5.75			5.75
Senior secured leverage ratio	3.50			3.50
Interest coverage ratio	3.00			3.00