Property and Equipment - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Gross property and equipment	$ 90,652	$ 160,190
Less: Accumulated depreciation	(51,527)	(42,472)
Property and equipment, net	39,125	117,718
Building
Property Plant And Equipment [Line Items]
Gross property and equipment	0	71,780
Computer Equipment
Property Plant And Equipment [Line Items]
Gross property and equipment	23,060	21,448
Leasehold Improvements
Property Plant And Equipment [Line Items]
Gross property and equipment	56,191	56,396
Furniture, Fixtures, and Other Assets
Property Plant And Equipment [Line Items]
Gross property and equipment	$ 11,401	$ 10,566