Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Payroll and benefits	$ 84,558	$ 124,943
Short-term operating lease liability	29,835	0
Income taxes payable	27,114	38,567
Accrued interest	20,062	10,302
Deferred revenue and customer advances	16,573	16,736
Accrued severance plan obligations	14,697	13,179
Other accrued expenses	52,957	54,482
Total accrued expenses	$ 245,796	$ 258,209