Accounts Payable, Accrued, and Other Liabilities (Details) - Accounts Payable and Accrued Liabilities - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Accounts payable	$ 49,000	$ 41,009
Payroll and employee benefits payable	120,278	87,821
Severance and retention bonus payable	44,685	22,425
Bonus payable	162,710	105,549
Commissions payable	108,969	68,273
Taxes payable	46,758	20,378
Other accrued liabilities	134,421	95,316
Total accounts payable and accrued liabilities	$ 666,821	$ 440,771