Summary of Significant Accounting Policies - Prepaid Expenses and Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Accounting Policies [Abstract]
Minimum percentage of current assets and liabilities required to be disclosed separately	5.00%
Income tax receivable	$ 33,173	$ 41,559
Other	109,778	97,910
Prepaid expenses	142,951	139,469
Interest	68,316	69,525
Payroll and vacation	50,143	75,050
Incentive compensation	61,422	66,552
Self-insured liabilities	33,508	33,381
Other	137,672	159,977
Accrued expenses	$ 351,061	$ 404,485