Accounts Payable, Accrued Expenses and Other Liabilities - Components of Current Portion of Accounts Payable, Accrued Expenses and Other Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accounts Payable Accrued Expenses And Other Liabilities Current [Abstract]
Accounts payable and accrued expenses	$ 189,172	$ 113,713
Outside broker payable	74,280	59,918
Payroll taxes payable	45,612	39,620
Corporate and other taxes payable	69,237	77,858
Derivative liability	25,661	16,678
Contingent consideration	13,107	4,452
Current portion of accounts payable, accrued expenses and other liabilities	$ 417,069	$ 312,239