Fair Value of Financial Instruments Financial Instruments Carried at Historical Cost(Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$ 2,273,058	$ 2,157,338
Long-term debt, Fair Value	2,303,531	2,158,121
Revolving credit facility [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	74,297	39,737
Long-term debt, Fair Value	81,192	44,833
Other debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	4,882	3,123
Long-term debt, Fair Value	4,889	3,090
Credit Agreement [Member] | United States Term Loan [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	1,415,873	1,755,736
Long-term debt, Fair Value	1,422,512	1,750,040
Credit Agreement [Member] | U.K. term loan [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	121,149	149,500
Long-term debt, Fair Value	121,594	150,030
Credit Agreement [Member] | Australian Term Loan [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	0	209,242
Long-term debt, Fair Value	0	210,128
Australia Credit Agreement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	484,703	0
Long-term debt, Fair Value	501,909	0
Australian Partner Loan Agreement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	172,154	0
Long-term debt, Fair Value	$ 171,435	$ 0