Leases - Material Office Leases (Details) $ in Thousands	Dec. 31, 2019 USD ($)
Lessee, Lease, Description [Line Items]
Future Minimum Lease Commitments	$ 103,242
Lease Agreements
Lessee, Lease, Description [Line Items]
Letter of Credit Amount Required	$ 3,600
Arlington, VA | Lease Agreements
Lessee, Lease, Description [Line Items]
Lease Termination Term (in years)	12 years 1 month 6 days
Future Minimum Lease Commitments	$ 40,832
Letter of Credit Amount Required	$ 1,579
Chicago, IL | Lease Agreements
Lessee, Lease, Description [Line Items]
Lease Termination Term (in years)	11 years 3 months 18 days
Future Minimum Lease Commitments	$ 41,857
Letter of Credit Amount Required	$ 232
Louisville, KY | Lease Agreements
Lessee, Lease, Description [Line Items]
Lease Termination Term (in years)	6 years 6 months
Future Minimum Lease Commitments	$ 0
Letter of Credit Amount Required	0
Prepaid rent	$ 4,300
Pune, India | Lease Agreements
Lessee, Lease, Description [Line Items]
Lease Termination Term (in years)	3 years 9 months 18 days
Future Minimum Lease Commitments	$ 3,265
Letter of Credit Amount Required	$ 0
Brea, CA | Lease Agreements
Lessee, Lease, Description [Line Items]
Lease Termination Term (in years)	2 years 4 months 24 days
Future Minimum Lease Commitments	$ 2,547
Letter of Credit Amount Required	$ 0