Revenues from Contracts with Customers - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Deferred Revenue Arrangement [Line Items]
Deferred revenue			$ 7,400	$ 1,300
Contract liabilities	$ 5,965		5,965		$ 7,856
Accounts Payable, Accrued Expenses and Other Liabilities
Deferred Revenue Arrangement [Line Items]
Contract liabilities	1,400		$ 1,400		$ 1,100
Advisory Services
Deferred Revenue Arrangement [Line Items]
Explanation of remaining performance obligations expected to be recognized as revenue			the Company generally expects to recognize this revenue within the next twelve months.
Revenue recognized related to performance obligations that were fully satisfied in prior periods	$ 4,600	$ 5,900	$ 9,200	$ 12,100