Accumulated Other Comprehensive Income (Loss) by Component (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022
Balance	$ 673,459	$ 677,157	$ 675,813	$ 679,628	$ 677,157	$ 679,628
Other comprehensive income (loss), net of tax:	1,765	(1,296)	(15,760)	(8,820)	469	(24,580)
Balance	671,303	673,459	670,812	675,813	671,303	670,812
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Balance	(59,119)	(63,106)	(29,699)	(6,272)	(63,106)	(6,272)
Other comprehensive income before reclassifications, net of tax	(7,349)		(20,434)		(4,216)	(43,861)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	2,945		0		3,799
Other comprehensive income (loss), net of tax:	(4,404)		(20,434)		(417)	(43,861)
Balance	(63,523)	(59,119)	(50,133)	(29,699)	(63,523)	(50,133)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Balance	20,240	25,380	13,345	(1,406)	25,380	(1,406)
Other comprehensive income before reclassifications, net of tax	10,991		3,285		8,799	16,177
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	(4,672)		1,630		(7,620)	3,489
Other comprehensive income (loss), net of tax:	6,319		4,915		1,179	19,666
Balance	26,559	20,240	18,260	13,345	26,559	18,260
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Balance	(344)	(275)	(1,291)	(1,282)	(275)	(1,282)
Other comprehensive income before reclassifications, net of tax			0
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	(69)		(22)		(138)	(31)
Other comprehensive income (loss), net of tax:	(69)		(22)		(138)	(31)
Balance	(413)	(344)	(1,313)	(1,291)	(413)	(1,313)
Accumulated Gain (Loss), Financial Liability, Fair Value Option, Attributable to Parent [Member]
Balance	1,439	1,513	2,141	2,276	1,513	2,276
Other comprehensive income before reclassifications, net of tax	(81)		(219)		(155)	(354)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax			0
Other comprehensive income (loss), net of tax:	(81)		(219)		(155)	(354)
Balance	1,358	1,439	1,922	2,141	1,358	1,922
AOCI Attributable to Parent [Member]
Balance	(37,784)	(36,488)	(15,504)	(6,684)	(36,488)	(6,684)
Other comprehensive income before reclassifications, net of tax	3,561		(17,368)		4,428	(28,038)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	(1,796)		1,608		(3,959)	3,458
Other comprehensive income (loss), net of tax:	1,765	(1,296)	(15,760)	(8,820)	469	(24,580)
Balance	$ (36,019)	$ (37,784)	$ (31,264)	$ (15,504)	$ (36,019)	$ (31,264)