Leases Leases (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Operating Lease, Cost	$ 4,100	$ 11,700
Operating Lease, Payments		12,500
Lessee Operating Lease Leases Not Yet Commenced Amount	8,200	8,200
Right-of-use leased assets	$ 58,185	$ 58,185	$ 50,800	$ 0
Operating Lease, Weighted Average Remaining Lease Term	6 years	6 years
Operating Lease, Liability, Current	$ 15,195	$ 15,195
Operating lease liabilities, net of current	60,132	60,132		$ 0
Landlord funded tenant improvements	12,711	12,711
Deferred Rent Credit, Noncurrent	$ 4,431	$ 4,431
Operating Lease, Weighted Average Discount Rate, Percent	4.60%	4.60%
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year	$ 4,564	$ 4,564
Lessee, Operating Lease, Liability, Payments, Due Year Two	17,656	17,656
Lessee, Operating Lease, Liability, Payments, Due Year Three	15,049	15,049
Lessee, Operating Lease, Liability, Payments, Due Year Four	13,637	13,637
Lessee, Operating Lease, Liability, Payments, Due Year Five	11,134	11,134
Lessee, Operating Lease, Liability, Payments, Due after Year Five	24,174	24,174
Lessee, Operating Lease, Liability, Payments, Due	86,214	86,214
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	10,887	10,887
Operating Lease, Liability	$ 75,327	$ 75,327	$ 63,700
Minimum [Member]
Lessee, Operating Lease, Lease Not yet Commenced, Term of Contract	4 years	4 years
Maximum [Member]
Lessee, Operating Lease, Lease Not yet Commenced, Term of Contract	8 years	8 years