Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 11,732	$ 10,887	$ 33,325	$ 30,609
Unrealized gains (losses) on securities:
Unrealized gains (losses) arising during period	(208)	486	932	445
Less: reclassification adjustment for gains included in net income	0	0	0	0
Total unrealized gains (losses) on securities	(208)	486	932	445
Accretion of net unrealized losses transferred	128	145	391	471
Defined benefit pension plans:
Amortization of prior service cost and loss included in net periodic benefit cost	406	360	1,218	1,081
Other comprehensive income (loss)	326	991	2,541	1,997
Comprehensive income	$ 12,058	$ 11,878	$ 35,866	$ 32,606