Accumulated Other Comprehensive Income (Loss) - Components of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 623,096	$ 593,179	$ 622,322	$ 612,227
Other comprehensive income (loss)	4,644	150	(4,150)	6,832
Ending balance	644,012	603,674	644,012	603,674
Net Change in Unrealized Gains on Available-for- Sale Investment Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	6,024	10,569	10,954	3,910
Other comprehensive income (loss)	1,034	127	(3,896)	6,786
Ending balance	7,058	10,696	7,058	10,696
Net Change in Fair Value of Derivative Used for Cash Flow Hedge
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(3,916)	0	0	0
Other comprehensive income (loss)	3,583	0	(333)	0
Ending balance	(333)	0	(333)	0
Net Change in Unfunded Pension Liability
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(1,954)	(1,700)	(2,006)	(1,723)
Other comprehensive income (loss)	27	23	79	46
Ending balance	(1,927)	(1,677)	(1,927)	(1,677)
AOCI Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	154	8,869	8,948	2,187
Other comprehensive income (loss)	4,644	150	(4,150)	6,832
Ending balance	$ 4,798	$ 9,019	$ 4,798	$ 9,019