Accounts Payable and Accrued and Other Liabilities - Accounts Payable and Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Accounts payable	$ 32,995	$ 37,508
Payroll and employee benefits payable	165,449	143,803
Severance and retention bonus payable	24,281	28,292
Bonus payable	192,100	170,719
Commissions payable	142,499	126,844
Taxes payable	7,878	19,725
Current portion of operating lease liabilities	76,516
Other accrued liabilities	147,078	183,222
Total accounts payable and accrued liabilities	$ 788,796	$ 710,113