Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Leases
Operating Lease Cost	$ 1,370	$ 1,445	$ 2,776	$ 2,927
Variable Lease Cost	320	892	675	1,210
Sublease Income	42		42
Total Lease Cost	1,648	2,337	3,409	4,137
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from operating leases	1,503	1,402	2,990	2,797
Right-of-use assets obtained in exchange for new operating lease liabilities		231	15	951
Reduction to right-of-use asset resulting from reduction to lease liability		$ 1,279		$ 1,279
Other non-cash reductions to right of use assets			1,192
Operating lease right-of-use assets	$ 18,648		$ 18,648		$ 22,335
Operating lease, right-of-use asset, Statement of Financial Position	us-gaap:OtherAssets		us-gaap:OtherAssets
Operating Lease Liabilities	$ 21,766		$ 21,766		$ 24,475
Operating lease liability, Statement of Financial Position	us-gaap:OtherLiabilities		us-gaap:OtherLiabilities
Weighted-average remaining lease term - operating leases	4 years 3 months 3 days		4 years 3 months 3 days		4 years 8 months 8 days
Weighted-average discount rate - operating leases	2.34%		2.34%		2.33%
Minimum
Leases
Remaining lease terms - operating leases	1 year
Maximum
Leases
Remaining lease terms - operating leases	15 years