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
Balance at Dec. 31, 2019	$ 39	$ 132,292	$ 1,973,700	$ (365,186)	$ (37,310)	$ (22,967)	$ 1,680,568
Net income (loss)	0	0		(17,185)	0	0	(17,185)
Restricted stock units granted	0	0	1,219	0	0	0	1,219
Common stock dividends declared	0	0	0	(1,304)	0	0	(1,304)
Series B Preferred Stock dividends declared	0	0	0	(138)	0	0	(138)
Common stock issued for 401(k) match	0	89	1,114	0	0	0	1,203
Other comprehensive income (loss)	0	0	0	0	(19,335)	0	(19,335)
Balances at Mar. 31, 2020	39	132,381	1,976,033	(383,813)	(56,645)	(22,967)	1,645,028
Balance at Dec. 31, 2020	39	134,629	2,003,576	(391,374)	(32,889)	(23,496)	1,690,485
Net income (loss)	0	0		18,971	0	0	18,971
Restricted stock units granted	0	0	483	0	0	0	483
Common stock dividends declared	0	0	0	(4,688)	0	0	(4,688)
Series B Preferred Stock dividends declared	0	0	0	(138)	0	0	(138)
Common stock issued for 401(k) match	0	42	1,088	0	0	0	1,130
Shares issued to pension plans	0	875	15,925	0	0	0	16,800
Other comprehensive income (loss)	0	0	0	0	1,832	0	1,832
Balances at Mar. 31, 2021	$ 39	$ 135,546	$ 2,021,072	$ (377,229)	$ (31,057)	$ (23,496)	$ 1,724,875