(Accounts Payable and Accrued Expenses) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Balance Sheet Related Disclosures [Abstract]
Accounts payable—seller	$ 166,085	$ 228,850
Accounts payable—trade	8,492	6,962
Accrued employee-related payables	10,822	12,155
Accounts payable and accrued expenses	$ 185,399	$ 247,967