Accumulated Other Comprehensive Income - Unrealized gains (losses) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ (126,630)	$ 1,412	$ (2,426)	$ 9,764
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(40,745)	(2,514)	(164,949)	(10,866)
Ending balance	(167,375)	(1,102)	(167,375)	(1,102)
Unrealized gain (loss) on securities available-for-sale
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(109,159)	24,866	15,674	34,162
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(41,060)	(2,985)	(165,893)	(12,281)
Ending balance	(150,219)	21,881	(150,219)	21,881
Unrealized gains (losses) on securities available-for-sale with other than temporary impairment
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	2,315	2,449	2,519	2,352
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	18	(16)	(186)	81
Ending balance	2,333	2,433	2,333	2,433
Unrealized gains (losses) on securities available-for-sale without other than temporary impairment
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(111,474)	22,417	13,155	31,810
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(41,078)	(2,969)	(165,707)	(12,362)
Ending balance	(152,552)	19,448	(152,552)	19,448
Retirement plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(17,471)	(23,454)	(18,100)	(24,398)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	315	471	944	1,415
Ending balance	$ (17,156)	$ (22,983)	$ (17,156)	$ (22,983)