Fixed Assets and Capitalized Software - Schedule of Depreciation and Amortization (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Amortization of capitalized software	$ 20,718	$ 25,913	$ 29,584
Depreciation of fixed assets	10,192	14,007	16,537
Total depreciation and amortization expense	30,910	39,920	46,121
Assets under leaseback obligations
Property, Plant and Equipment [Line Items]
Depreciation of fixed assets	$ 1,700	$ 1,700	$ 1,700