Condensed Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Treasury Stock [Member]	Total
Balances, July 1, 2021 (Revised) at Dec. 31, 2019	$ 39	$ 132,292	$ 1,973,700	$ (349,220)	$ (37,310)	$ (22,967)	$ 1,696,534
Net income (loss)							(27,842)
Balances at Jun. 30, 2020	39	133,699	1,982,400	(380,205)	(46,261)	(23,496)	1,666,176
Balances, July 1, 2021 (Revised) at Dec. 31, 2019	39	132,292	1,973,700	(349,220)	(37,310)	(22,967)	1,696,534
Net income (loss)	0	0	0	(12,562)	0	0	(12,562)
Restricted stock units granted	0	0	3,746	0	0	0	3,746
Common stock dividends declared	0	0	0	(3,951)	0	0	(3,951)
Series B Preferred Stock dividends declared	0	0	0	(414)	0	0	(414)
Common stock issued for 401(k) match	0	350	3,295	0	0	0	3,645
Common stock issued to pension plans	0	555	12,226	0	0	0	12,781
Other comprehensive income (loss)	0	0	0	0	(2,801)	0	(2,801)
Common stock issued to directors	0	98	1,385	0	0	0	1,483
Restricted stock unit distributions	0	426	(426)	0	0	(1,479)	(1,479)
Common stock issued for employee incentive compensation	0	700	4,396	0	0	(1,266)	3,830
Treasury shares issued to charitable foundation	0	0	0	(246)	0	2,216	1,970
Balances at Sep. 30, 2020	39	134,421	1,998,322	(366,393)	(40,111)	(23,496)	1,702,782
Balances, July 1, 2021 (Revised) at Dec. 31, 2019	39	132,292	1,973,700	(349,220)	(37,310)	(22,967)	1,696,534
Net income (loss)							(9,457)
Balances at Dec. 31, 2020	39	134,629	2,003,576	(368,074)	(32,889)	(23,496)	1,713,785
Balances, July 1, 2021 (Revised) at Jun. 30, 2020	39	133,699	1,982,400	(380,205)	(46,261)	(23,496)	1,666,176
Net income (loss)	0	0	0	15,280	0	0	15,280
Restricted stock units granted	0	0	1,317	0	0	0	1,317
Common stock dividends declared	0	0	0	(1,330)	0	0	(1,330)
Series B Preferred Stock dividends declared	0	0	0	(138)	0	0	(138)
Common stock issued for 401(k) match	0	110	1,303	0	0	0	1,413
Common stock issued to pension plans	0	514	11,917	0	0	0	12,431
Other comprehensive income (loss)	0	0	0	0	6,150	0	6,150
Common stock issued to directors	0	98	1,385	0	0	0	1,483
Balances at Sep. 30, 2020	39	134,421	1,998,322	(366,393)	(40,111)	(23,496)	1,702,782
Balances, July 1, 2021 (Revised) at Dec. 31, 2020	39	134,629	2,003,576	(368,074)	(32,889)	(23,496)	1,713,785
Net income (loss)							24,199
Balances at Jun. 30, 2021	39	136,065	2,024,645	(354,866)	(29,437)	(28,021)	1,748,425
Balances, July 1, 2021 (Revised) at Dec. 31, 2020	39	134,629	2,003,576	(368,074)	(32,889)	(23,496)	1,713,785
Net income (loss)	0	0	0	23,220	0	0	23,220
Restricted stock units granted	0	0	2,930	0	0	0	2,930
Common stock dividends declared	0	0	0	(16,755)	0	0	(16,755)
Series B Preferred Stock dividends declared	0	0	0	(414)	0	0	(414)
Common stock issued for 401(k) match	0	131	3,324	0	0	0	3,455
Common stock issued to pension plans	0	1,125	21,125	0	0	0	22,250
Other comprehensive income (loss)	0	0	0	0	(2,815)	0	(2,815)
Common stock issued to directors	0	52	1,792	0	0	0	1,844
Restricted stock unit distributions	0	413	(413)	0	0	(4,525)	(4,525)
Balances at Sep. 30, 2021	39	136,350	2,032,334	(362,023)	(35,704)	(28,021)	1,742,975
Balances, July 1, 2021 (Revised) at Jun. 30, 2021	39	136,065	2,024,645	(354,866)	(29,437)	(28,021)	1,748,425
Net income (loss)	0	0	0	(979)	0	0	(979)
Restricted stock units granted	0	0	1,472	0	0	0	1,472
Common stock dividends declared	0	0	0	(6,040)	0	0	(6,040)
Series B Preferred Stock dividends declared	0	0	0	(138)	0	0	(138)
Common stock issued for 401(k) match	0	35	1,017	0	0	0	1,052
Common stock issued to pension plans	0	250	5,200	0	0	0	5,450
Other comprehensive income (loss)	0	0	0	0	(6,267)	0	(6,267)
Balances at Sep. 30, 2021	$ 39	$ 136,350	$ 2,032,334	$ (362,023)	$ (35,704)	$ (28,021)	$ 1,742,975