Long-term Debt Outstanding Term Loans (Details) £ in Thousands, AUD in Thousands, $ in Thousands	Dec. 31, 2015 AUD	Dec. 31, 2015 GBP (£)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Debt Instrument [Line Items]
Long-term debt			$ 2,180,847	$ 1,603,772
United States term loan [Member]
Debt Instrument [Line Items]
Long-term debt			1,772,000	1,407,000
Australian term loan [Member]
Debt Instrument [Line Items]
Long-term debt			210,993	133,857
U.K. term loan [Member]
Debt Instrument [Line Items]
Long-term debt			149,919	$ 0
Loans Payable [Member] | United States term loan [Member]
Debt Instrument [Line Items]
Long-term debt			$ 1,772,000
Debt instrument, interest rate, stated percentage	2.42%	2.42%	2.42%
Loans Payable [Member] | Australian term loan [Member]
Debt Instrument [Line Items]
Long-term debt	AUD 289,627		$ 210,993
Debt instrument, interest rate, stated percentage	4.12%	4.12%	4.12%
Loans Payable [Member] | U.K. term loan [Member]
Debt Instrument [Line Items]
Long-term debt		£ 101,681	$ 149,919
Debt instrument, interest rate, stated percentage	2.51%	2.51%	2.51%