Leases - Narrative (Details) - USD ($)	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Operating Lease, Right-of-Use Asset	$ 20,737,000	$ 13,714,000
Operating Lease, Liability	$ 21,482,000	$ 14,482,000
Operating Lease, Weighted Average Remaining Lease Term	8 years 1 month 6 days	7 years 2 months 12 days
Operating Lease, Weighted Average Discount Rate, Percent	2.60%	3.10%
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 981,877,000	$ 969,014,000
Deferred Rent Credit				$ 600,000
Other Assets [Member]
Operating Lease, Right-of-Use Asset	20,700,000	13,700,000		11,000,000.0
Other Liabilities [Member]
Operating Lease, Liability	21,482,000	14,500,000		11,800,000
Retained Earnings [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 649,636,000	$ 646,847,000	$ 619,971,000	614,069,000
Accounting Standards Update 2016-02 [Member] | Retained Earnings [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest				613,926,000
Accounting Standards Update 2016-02 [Member] | Retained Earnings [Member] | Cumulative Effect, Period of Adoption, Adjustment
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest				$ (143,000)