Leases Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Lessee Operating Lease Leases Not Yet Commenced Amount	$ 20,500
Right-of-use leased assets	$ 50,259	$ 50,800	$ 0
Operating Lease, Weighted Average Remaining Lease Term	6 years
Operating Lease, Liability, Current	$ 13,065
Operating lease liabilities, net of current	50,371		$ 0
Total Operating Lease Liability	63,436	$ 63,700
Landlord funded tenant improvements	$ 9,368
Operating Lease, Weighted Average Discount Rate, Percent	4.80%
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year	$ 11,791
Lessee, Operating Lease, Liability, Payments, Due Year Two	14,194
Lessee, Operating Lease, Liability, Payments, Due Year Three	11,282
Lessee, Operating Lease, Liability, Payments, Due Year Four	9,945
Lessee, Operating Lease, Liability, Payments, Due Year Five	7,631
Lessee, Operating Lease, Liability, Payments, Due after Year Five	18,631
Lessee, Operating Lease, Liability, Payments, Due	73,474
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	10,038
Operating Lease, Liability	$ 63,436
Minimum [Member]
Lessee, Operating Lease, Lease Not yet Commenced, Term of Contract	4 years
Maximum [Member]
Lessee, Operating Lease, Lease Not yet Commenced, Term of Contract	7 years