Leases - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Operating Leased Assets [Line Items]
Operating lease, right of use asset	$ 71,367		$ 73,597
Right of use asset obtained in exchange for operating lease liability	0	$ 0
UNITED STATES
Operating Leased Assets [Line Items]
Operating lease, right of use asset	61,000		62,200
Operating lease, liability	81,200		82,900
UNITED STATES | Northern Virginia Office Space
Operating Leased Assets [Line Items]
Operating lease, right of use asset	58,100		59,000
Operating lease, liability	78,200		79,700
Non-US
Operating Leased Assets [Line Items]
Operating lease, right of use asset	10,400		11,400
Operating lease, liability	$ 11,300		$ 12,200