Condensed Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Voting Common Stock [Member] Common Stock [Member]	Voting Common Stock [Member]	Nonvoting Common Stock [Member] Common Stock [Member]	Nonvoting Common Stock [Member]	Paid-In Capital [Member]	Treasury Stock Voting [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]	Total
Balance at Dec. 31, 2019	$ 216		$ 95		$ 1,019,988	$ (9,592)	$ (605,766)	$ (54,914)	$ 350,027
Balance, shares at Dec. 31, 2019	21,582,000		9,506,000			154,000
Net income (loss)							(47,777)
Other comprehensive income (loss)								14,111
Comprehensive (loss) income									(33,666)
Common dividend paid							(170,130)		(170,130)
Balance at Jun. 30, 2020	$ 216		$ 95		1,019,988	$ (9,592)	(823,673)	(40,803)	146,231
Balance, shares at Jun. 30, 2020	21,582,000		9,506,000			154,000
Balance at Dec. 31, 2019	$ 216		$ 95		1,019,988	$ (9,592)	(605,766)	(54,914)	350,027
Balance, shares at Dec. 31, 2019	21,582,000		9,506,000			154,000
Net income (loss)									3,395
Other comprehensive income (loss)									6,891
Comprehensive (loss) income									10,286
Balance at Sep. 30, 2020	$ 216		$ 95		1,019,988	$ (9,592)	(772,501)	(48,023)	190,183
Balance, shares at Sep. 30, 2020	21,582,000		9,506,000			154,000
Balance at Dec. 31, 2019	$ 216		$ 95		1,019,988	$ (9,592)	(605,766)	(54,914)	350,027
Balance, shares at Dec. 31, 2019	21,582,000		9,506,000			154,000
Other comprehensive income (loss)								(17,058)
Balance at Dec. 31, 2020	$ 216		$ 95		1,019,988	$ (9,592)	(729,202)	(71,972)	209,533
Balance, shares at Dec. 31, 2020	21,582,000	21,581,572	9,506,000	9,505,673		154,000
Balance at Jun. 30, 2020	$ 216		$ 95		1,019,988	$ (9,592)	(823,673)	(40,803)	146,231
Balance, shares at Jun. 30, 2020	21,582,000		9,506,000			154,000
Net income (loss)							51,172		51,172
Other comprehensive income (loss)								(7,220)	(7,220)
Comprehensive (loss) income									43,952
Balance at Sep. 30, 2020	$ 216		$ 95		1,019,988	$ (9,592)	(772,501)	(48,023)	190,183
Balance, shares at Sep. 30, 2020	21,582,000		9,506,000			154,000
Net income (loss)							89,698
Other comprehensive income (loss)								(23,949)
Comprehensive (loss) income									65,749
Common dividend paid							(46,399)		(46,399)
Balance at Dec. 31, 2020	$ 216		$ 95		1,019,988	$ (9,592)	(729,202)	(71,972)	209,533
Balance, shares at Dec. 31, 2020	21,582,000	21,581,572	9,506,000	9,505,673		154,000
Net income (loss)							52,207
Other comprehensive income (loss)								(3,601)
Comprehensive (loss) income									48,606
Balance at Jun. 30, 2021	$ 216		$ 95		1,019,988	$ (9,592)	(676,995)	(75,573)	258,139
Balance, shares at Jun. 30, 2021	21,582,000		9,506,000			154,000
Balance at Dec. 31, 2020	$ 216		$ 95		1,019,988	$ (9,592)	(729,202)	(71,972)	209,533
Balance, shares at Dec. 31, 2020	21,582,000	21,581,572	9,506,000	9,505,673		154,000
Net income (loss)									26,999
Other comprehensive income (loss)								4,742	4,742
Comprehensive (loss) income									31,741
Balance at Sep. 30, 2021	$ 216		$ 95		1,019,988	$ (9,592)	(702,203)	(67,230)	241,274
Balance, shares at Sep. 30, 2021	21,582,000	21,581,572	9,506,000	9,505,673		154,000
Balance at Jun. 30, 2021	$ 216		$ 95		1,019,988	$ (9,592)	(676,995)	(75,573)	258,139
Balance, shares at Jun. 30, 2021	21,582,000		9,506,000			154,000
Net income (loss)							(25,208)		(25,208)
Other comprehensive income (loss)								8,343	8,343
Comprehensive (loss) income									(16,865)
Balance at Sep. 30, 2021	$ 216		$ 95		$ 1,019,988	$ (9,592)	$ (702,203)	$ (67,230)	$ 241,274
Balance, shares at Sep. 30, 2021	21,582,000	21,581,572	9,506,000	9,505,673		154,000