Revenues and Business Information - Schedule of Geographical Distribution of Revenues and Assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues	$ 159,938	$ 153,523	$ 313,644	$ 291,306
Total assets	973,944		973,944		$ 1,071,699
United States
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues	138,382	132,246	267,567	254,926
Total assets	881,086		881,086		934,654
Europe
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues	15,124	16,005	31,380	22,721
Total assets	30,729		30,729		67,247
Rest of World
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues	6,432	$ 5,272	14,697	$ 13,659
Total assets	$ 62,129		$ 62,129		$ 69,798