Leases (Details) $ in Thousands		3 Months Ended
	Jul. 01, 2018 Floor	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)
Lessee, Lease, Description [Line Items]
Operating Lease, Cost		$ 11,916	$ 10,235
Variable Lease, Cost		1,723	1,597
Operating Lease Additional Floors | Floor	7
Operating Lease Additional Floors Commencing on Lease Effective Date | Floor	3
Operating Lease, Payments		9,102	2,973
Operating Lease, Incentive Payments Received		1,270	6,198
Lessee, Additional Payments for Operating Leases Not Yet Commenced		$ 203,291
Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Lease Not yet Commenced, Term of Contract		1 year
Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Lease Not yet Commenced, Term of Contract		13 years
Office Equipment [Member]
Lessee, Lease, Description [Line Items]
Operating Lease, Cost		$ 1,196	$ 923
Letter of Credit [Member]
Lessee, Lease, Description [Line Items]
Other Assets		$ 5,545		$ 5,536