Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Components of accrued expenses
Accrued investment manager fees	$ 44,154	$ 39,324
Accrued compensation and related taxes	38,597	43,724
Sales and use tax payable	9,408	9,037
Accrued professional services	4,432	4,985
Accrued interest	864
Definite consideration		1,250
Other accrued expenses	12,082	7,577
Total accrued expenses	$ 109,537	$ 105,897