Accumulated Other Comprehensive Income (Loss) (AOCI) - Changes in AOCI by Component (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Changes in AOCI by Component
Balance at the beginning of the period, net of taxes	$ (12,730)
Net current period other comprehensive income (loss), net of taxes	142	$ 2,539
Balance at the end of the period, net of taxes	(12,588)
Accumulated Other Comprehensive Loss
Changes in AOCI by Component
Balance at the beginning of the period, net of taxes	(12,730)	(16,856)
Other comprehensive income (loss) before reclassification, net of taxes	160	2,563
Amounts reclassified from other comprehensive income (loss), net of taxes	(18)	(24)
Net current period other comprehensive income (loss), net of taxes	142	2,539
Balance at the end of the period, net of taxes	(12,588)	(14,317)
Unrealized Gains (Losses) on Available-for-Sale Securities and I/O Strips
Changes in AOCI by Component
Balance at the beginning of the period, net of taxes	(7,029)	(11,394)
Other comprehensive income (loss) before reclassification, net of taxes	176	2,577
Net current period other comprehensive income (loss), net of taxes	176	2,577
Balance at the end of the period, net of taxes	(6,853)	(8,817)
Defined Benefit Pension Plan Items
Changes in AOCI by Component
Balance at the beginning of the period, net of taxes	(5,701)	(5,462)
Other comprehensive income (loss) before reclassification, net of taxes	(16)	(14)
Amounts reclassified from other comprehensive income (loss), net of taxes	(18)	(24)
Net current period other comprehensive income (loss), net of taxes	(34)	(38)
Balance at the end of the period, net of taxes	$ (5,735)	$ (5,500)