Summary of Significant Accounting Policies - Cumulative Effect of ASC 842 (Details) - USD ($) $ in Thousands	Dec. 31, 2020		Jan. 01, 2020	Dec. 31, 2019
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Operating lease right-of-use assets	$ 35,621		$ 28,121	$ 0
Assets	1,454,387		1,350,712	1,322,591
Operating lease liabilities	7,899		5,535	0
Accrued expenses and other current liabilities	112,004	[1]	68,970	70,284	[1]
Current liabilities	436,377		578,185	573,964
Operating lease liabilities, non-current	41,849		34,240	0
Other long-term liabilities	12,279	[1]	17,673	28,013	[1]
Liabilities	1,312,991		1,518,572	1,490,451
Total liabilities, redeemable noncontrolling interest, stockholders' deficit and noncontrolling interest	$ 1,454,387		$ 1,350,712	1,322,591
Revision of Prior Period, Accounting Standards Update, Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Operating lease right-of-use assets				28,121
Assets				28,121
Operating lease liabilities				5,535
Accrued expenses and other current liabilities				(1,314)
Current liabilities				4,221
Operating lease liabilities, non-current				34,240
Other long-term liabilities				(10,340)
Liabilities				28,121
Total liabilities, redeemable noncontrolling interest, stockholders' deficit and noncontrolling interest				$ 28,121

[1] We have variable interest entities, which represent a portion of the consolidated balances recorded within these financial statement line items in the consolidated balance sheets (see Note 13 - Portfolio Financings).