Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Consolidated Statements of Comprehensive Income (Unaudited) [Abstract]
Net income	$ 11,254	$ 14,667	$ 24,567	$ 29,225
Net unrealized holding gain (loss) on securities available for sale	927	7,177	11,659	11,767
Reclassification adjustments for net gain recognized in income	0	0	(1,155)	0
Tax effect	(242)	(1,864)	(2,729)	(3,058)
Net unrealized gain on securities available for sale, net of tax	685	5,313	7,775	8,709
Amortization of net actuarial gain	(143)	(20)	(309)	(68)
Amortization of prior service (credit) cost	(49)	(82)	(98)	(167)
Tax effect	51	26	107	61
Amortization of net actuarial gain and prior service credit on pension and postretirement plans, net of tax	(141)	(76)	(300)	(174)
Other comprehensive income, net of tax	544	5,237	7,475	8,535
Comprehensive income	$ 11,798	$ 19,904	$ 32,042	$ 37,760