Other Comprehensive Income (Loss) - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances at beginning	$ 717,689	$ 663,054	$ 620,871
Balances at ending	728,941	717,689	663,054
Available-for-Sale Debt Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances at beginning	20,609	4,039	(23,589)
Other comprehensive income (loss)	(35,169)	16,570	27,628
Balances at ending	(14,560)	20,609	4,039
Employee Benefit Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances at beginning	(52,683)	(47,603)	(39,576)
Other comprehensive income (loss)	11,293	(5,080)	(8,027)
Balances at ending	(41,390)	(52,683)	(47,603)
Accumulated Other Comprehensive Income (loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances at beginning	(32,074)	(43,564)	(63,165)
Other comprehensive income (loss)	(23,876)	11,490	19,601
Balances at ending	$ (55,950)	$ (32,074)	$ (43,564)