Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-in Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interest
Beginning balance (in shares) at Dec. 31, 2018			28,404,316
Beginning balance at Dec. 31, 2018	$ 889,312	$ 97	$ 28	$ 495,366	$ 393,918	$ 97	$ 0	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	23,627				23,403			224
Distribution to noncontrolling interest	(224)							(224)
Unrealized gain (loss) on investment, net of tax effect	117						117
Adjustment to pension benefit plans, net of taxes	9						9
Share-based compensation	3,313			3,406	(93)
Share-based compensation related to business combination	6,384			6,384
Issuance of restricted and deferred stock units (in shares)			21,909
Issuance of restricted and deferred stock units	$ (110)			(110)
Employee stock purchase plan (in shares)	30,255		30,283
Employee stock purchase plan	$ 1,603			1,603
Common stock issuance, net of costs	(10)			(10)
Dividends paid	(34,134)				(34,134)
Ending balance (in shares) at Dec. 31, 2019			28,456,508
Ending balance at Dec. 31, 2019	889,984		$ 28	506,639	383,191		126	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	61,515				61,515
Unrealized gain (loss) on investment, net of tax effect	(310)						(310)
Adjustment to pension benefit plans, net of taxes	(880)						(880)
Share-based compensation	3,393			3,553	(160)
Issuance of restricted and deferred stock units (in shares)			68,347
Issuance of restricted and deferred stock units	$ (1,863)		$ 1	(1,864)
Employee stock purchase plan (in shares)	31,750		31,750
Employee stock purchase plan	$ 1,830			1,830
Dividends paid	$ (36,509)				(36,509)
Ending balance (in shares) at Dec. 31, 2020	28,556,605		28,556,605
Ending balance at Dec. 31, 2020	$ 917,160		$ 29	510,158	408,037		(1,064)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	60,478				60,478
Unrealized gain (loss) on investment, net of tax effect	185						185
Adjustment to pension benefit plans, net of taxes	716						716
Share-based compensation	4,128			4,246	(118)
Issuance of restricted and deferred stock units (in shares)			49,824
Issuance of restricted and deferred stock units	$ (1,066)			(1,066)
Employee stock purchase plan (in shares)	35,304		35,304
Employee stock purchase plan	$ 2,026			2,026
Common stock issuance, net of costs (in shares)			1,539,615
Common stock issuance, net of costs	91,029		$ 1	91,028
Dividends paid	$ (40,137)				(40,137)
Ending balance (in shares) at Dec. 31, 2021	30,181,348		30,181,348
Ending balance at Dec. 31, 2021	$ 1,034,519		$ 30	$ 606,392	$ 428,260		$ (163)	$ 0