Condensed Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Director [Member] Preferred Stock [Member]	Director [Member] Common Stock [Member]	Director [Member] Additional Paid-in Capital [Member]	Director [Member] Retained Earnings [Member]	Director [Member] AOCI Attributable to Parent [Member]	Director [Member] Treasury Stock [Member]	Director [Member]	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Treasury Stock [Member]	Total
Balance at Dec. 31, 2018								$ 39	$ 121,956	$ 1,880,481	$ (248,308)	$ (42,469)	$ (20,736)	$ 1,690,963
Net income (loss)											(91,581)			(91,581)
Restricted stock units granted										4,303				4,303
Common stock dividends declared											(3,655)			(3,655)
Series B Preferred Stock dividends declared											(414)			(414)
Common stock issued for 401(k) match									327	2,425				2,752
Common stock issued to pension plans								0	597	3,003	0	0	0	3,600
Common stock issued for incentive compensation								0	899	7,375	0	0	(1,603)	6,671
Other comprehensive income (loss)												4,511		4,511
Restricted stock units distributed								0	291	(291)	0	0	(636)	(636)
Balance at Sep. 30, 2019								39	124,133	1,897,363	(343,958)	(37,958)	(22,975)	1,616,644
Adjustment to fair value of warrants issued for purchase of another company								0	0	(325)	0	0	0	(325)
Common stock issued to directors (253,000 shares)								0	63	392	0	0	0	455
Balance at Jun. 30, 2019								39	123,701	1,895,617	(323,079)	(34,670)	(22,380)	1,639,228
Net income (loss)											(19,516)			(19,516)
Restricted stock units granted										1,206				1,206
Common stock dividends declared											(1,225)			(1,225)
Series B Preferred Stock dividends declared											(138)			(138)
Common stock issued for 401(k) match									141	831				972
Other comprehensive income (loss)								0	0	0	0	(3,288)	0	(3,288)
Restricted stock units distributed								0	291	(291)	0	0	(595)	(595)
Balance at Sep. 30, 2019								39	124,133	1,897,363	(343,958)	(37,958)	(22,975)	1,616,644
Balance at Dec. 31, 2019								39	132,292	1,973,700	(353,331)	(37,310)	(22,967)	1,692,423
Net income (loss)											(17,585)			(17,585)
Restricted stock units granted										3,746				3,746
Common stock dividends declared											(3,951)			(3,951)
Series B Preferred Stock dividends declared											(414)			(414)
Common stock issued for 401(k) match									350	3,295				3,645
Common stock issued to pension plans								0	555	12,226	0	0	0	12,781
Common stock issued for incentive compensation	$ 0	$ 98	$ 1,385	$ 0	$ 0	$ 0	$ 1,483	0	700	4,396	0	0	(1,266)	3,830
Other comprehensive income (loss)								0	0	0	0	(2,801)	0	(2,801)
Restricted stock units distributed								0	426	(426)	0	0	(1,479)	(1,479)
Balance at Sep. 30, 2020								39	134,421	1,998,322	(375,527)	(40,111)	(23,496)	1,693,648
Treasury shares issued to charitable foundation								0	0	0	(246)	0	2,216	1,970
Balance at Jun. 30, 2020								39	133,699	1,982,400	(387,688)	(46,261)	(23,496)	1,658,693
Net income (loss)								0	0	0	13,628	0	0	13,628
Restricted stock units granted										1,317				1,317
Common stock dividends declared											(1,329)			(1,329)
Series B Preferred Stock dividends declared											(138)			(138)
Common stock issued for 401(k) match									110	1,303				1,413
Common stock issued to pension plans								0	514	11,917	0	0	0	12,431
Common stock issued for incentive compensation	$ 0	$ 98	$ 1,385	$ 0	$ 0	$ 0	$ 1,483
Other comprehensive income (loss)												6,150		6,150
Balance at Sep. 30, 2020								$ 39	$ 134,421	$ 1,998,322	$ (375,527)	$ (40,111)	$ (23,496)	$ 1,693,648