CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock [Member]	Common Stock [Member] Class A Common Stock [Member]	Treasury Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total	Class A Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment					$ 0
Beginning balance at Dec. 31, 2016	$ 28,793	$ 2,340	$ (111,412)	$ 86,273	277,707	$ (1,830)
Balance (in shares) at Dec. 31, 2016	28,793	2,340	(10,028)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Class A conversion	$ 50	$ (50)
Conversion of Class A Common Stock (in shares)	50	(50)
Stock compensation transactions, net	$ 107
Stock compensation transactions, net (in shares)	107
Restricted stock issuances				(1,662)
Director's compensation plan			$ 90	549
Directors' Compensation Plan (in shares)			8
Purchases			$ 0
Purchases (in shares)			0
Stock-based compensation				3,818
Net income					21,075		$ 21,075
Dividends declared					(11,392)			$ (919)
Pension liabilities adjustment, net of taxes						(314)
Ending balance at Dec. 31, 2017	$ 28,950	$ 2,290	$ (111,322)	88,978	287,390	(2,144)	294,142
Balance (in shares) at Dec. 31, 2017	28,950	2,290	(10,020)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment					133
Class A conversion	$ 10	$ (10)
Conversion of Class A Common Stock (in shares)	10	(10)
Stock compensation transactions, net	$ 119
Stock compensation transactions, net (in shares)	119
Restricted stock issuances				(1,352)
Director's compensation plan			$ 1,029	(590)
Directors' Compensation Plan (in shares)			88
Purchases			$ (18,732)
Purchases (in shares)			(890)
Stock-based compensation				4,358
Net income					30,307		30,307
Dividends declared					(35,464)			(2,869)
Pension liabilities adjustment, net of taxes						679
Ending balance at Dec. 31, 2018	$ 29,079	$ 2,280	$ (129,025)	91,394	282,366	(1,465)	274,629
Balance (in shares) at Dec. 31, 2018	29,079	2,280	(10,822)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment					6,824
Class A conversion	$ 226	$ (226)
Conversion of Class A Common Stock (in shares)	226	(226)
Stock compensation transactions, net	$ 126
Stock compensation transactions, net (in shares)	126
Restricted stock issuances				(1,568)
Director's compensation plan			$ 680	(53)
Directors' Compensation Plan (in shares)			55
Purchases			$ (29,757)
Purchases (in shares)			(1,605)
Stock-based compensation				3,435
Net income					21,865		21,865
Dividends declared					(15,056)			$ (1,143)
Pension liabilities adjustment, net of taxes						(622)
Ending balance at Dec. 31, 2019	$ 29,431	$ 2,054	$ (158,102)	$ 93,208	$ 295,999	$ (2,087)	$ 260,503
Balance (in shares) at Dec. 31, 2019	29,431	2,054	12,372