Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Payables and Accruals [Abstract]
Payroll and benefits	$ 113,302	$ 95,011
Deferred revenue and customer advances	52,543	49,243
Accrued settlement costs	33,552	32,987
Accrued interest	27,883	12,920
Income taxes payable	24,380	21,448
Accrued severance plan obligations	14,850	14,306
Other accrued expenses	39,775	38,297
Total accrued expenses	$ 306,285	$ 264,212