Condensed Consolidated Statements of Equity (unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-in- Capital	Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss Cumulative Effect, Period of Adoption, Adjustment	Company Shares Held by SERP	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Non-controlling Interest	Non-controlling Interest Cumulative Effect, Period of Adoption, Adjustment
Balance at Dec. 31, 2018	$ 585,290	$ 0	$ 4,503	$ 120,601	$ (33,883)	$ (721)	$ (1,886)	$ 495,245	$ 721	$ 710
Balance (in shares) at Dec. 31, 2018			22,513
Net income	37,579							37,651		(72)
Other comprehensive income	853				853					0
Dividends declared and paid	(4,956)			6				(4,962)
Stock-based compensation	1,773			1,773
Stock-based compensation (in shares)			2
RSU vesting			$ 3	(3)
RSU vesting (in shares)			16
Withholding tax paid upon vesting of RSUs	(160)			(160)
SERP transactions, net	238			68			170
Change in ownership percentage of subsidiary	(9)
Balance at Jun. 30, 2019	$ 620,608		$ 4,506	122,285	(33,751)		(1,716)	528,655		629
Balance (in shares) at Jun. 30, 2019			22,531
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201802Member
Balance at Mar. 31, 2019	$ 599,266	$ (9)	$ 4,505	121,665	(33,641)		(1,669)	507,759	$ 0	647	$ (9)
Balance (in shares) at Mar. 31, 2019			22,523
Net income	23,361							23,377		(16)
Other comprehensive income	(110)				(110)					0
Dividends declared and paid	(2,478)			3				(2,481)
Stock-based compensation	596			596
Stock-based compensation (in shares)			1
RSU vesting			$ 1	(1)
RSU vesting (in shares)			7
Withholding tax paid upon vesting of RSUs	0
SERP transactions, net	(25)			22			(47)
Other	7									7
Balance at Jun. 30, 2019	620,608		$ 4,506	122,285	(33,751)		(1,716)	528,655		629
Balance (in shares) at Jun. 30, 2019			22,531
Balance at Dec. 31, 2019	602,487		$ 4,510	122,613	(31,803)		(1,714)	508,343		538
Balance (in shares) at Dec. 31, 2019			22,551
Net income	29,788							29,902		(114)
Other comprehensive income	(8,799)				(8,662)					(137)
Dividends declared and paid	(4,970)			7				(4,977)
Stock-based compensation	3,760			3,760
Stock-based compensation (in shares)			1
RSU vesting			$ 10	(10)
RSU vesting (in shares)			51
Withholding tax paid upon vesting of RSUs	(565)			(565)
SERP transactions, net	125			36			89
Other	(2)									(2)
Balance at Jun. 30, 2020	621,824		$ 4,520	125,841	(40,465)		(1,625)	533,268		285
Balance (in shares) at Jun. 30, 2020			22,603
Balance at Mar. 31, 2020	612,477		$ 4,516	123,950	(41,013)		(1,752)	526,502		274
Balance (in shares) at Mar. 31, 2020			22,584
Net income	9,305							9,258		47
Other comprehensive income	513				548					(35)
Dividends declared and paid	(2,485)			7				(2,492)
Stock-based compensation	1,852			1,852
RSU vesting			$ 4	(4)
RSU vesting (in shares)			19
Withholding tax paid upon vesting of RSUs	0			0
SERP transactions, net	163			36			127
Other	(1)									(1)
Balance at Jun. 30, 2020	$ 621,824		$ 4,520	$ 125,841	$ (40,465)		$ (1,625)	$ 533,268		$ 285
Balance (in shares) at Jun. 30, 2020			22,603