Leases (Details) $ in Thousands		3 Months Ended		6 Months Ended
	Jul. 01, 2018 Floor	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Lessee, Lease, Description [Line Items]
Operating Lease, Cost		$ 12,108	$ 10,108	$ 24,024	$ 20,343
Variable Lease, Cost		1,132	3,221	2,855	4,818
Operating Lease Additional Floors | Floor	7
Operating Lease Additional Floors Commencing on Lease Effective Date | Floor	3
Operating Lease, Payments				11,763	8,485
Operating Lease, Incentive Payments Received				8,796	10,062
Lessee, Additional Payments for Operating Leases Not Yet Commenced		$ 196,129		$ 196,129
Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Lease Not yet Commenced, Term of Contract		3 years		3 years
Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Lease Not yet Commenced, Term of Contract		13 years		13 years
Office Equipment [Member]
Lessee, Lease, Description [Line Items]
Operating Lease, Cost		$ 1,132	$ 1,004	$ 2,328	$ 1,927
Letter of Credit [Member]
Lessee, Lease, Description [Line Items]
Other Assets		$ 5,548		$ 5,548		$ 5,536