Consolidated Statements of Comprehensive Income (Loss) (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Consolidated Statements of Comprehensive Income (Loss) (unaudited) [Abstract]
Net income	$ 33,658	$ 39,126
Securities available for sale:
Unrealized net holding gains (losses) arising during the period, gross	15,725	(91,030)
Tax effect	(3,931)	22,758
Unrealized net holding gains (losses) arising during the period, net	11,794	(68,272)
Reclassification adjustment for net losses in net income, gross	5,000	0
Tax effect	(1,250)	0
Reclassification adjustment for net losses in net income, net	3,750	0
Amortization of unrealized net gains for the reclassification of available for sale securities to held to maturity, gross	114	137
Tax effect	(28)	(35)
Amortization of unrealized net gains for the reclassification of available for sale securities to held to maturity, net	86	102
Total securities available for sale, net	15,630	(68,170)
Pension and other benefits:
Amortization of prior service cost and actuarial losses, gross	649	186
Tax effect	(163)	(47)
Amortization of prior service cost and actuarial losses, net	486	139
Total pension and other benefits, net	486	139
Total other comprehensive income (loss)	16,116	(68,031)
Comprehensive income (loss)	$ 49,774	$ (28,905)