Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Cumulative effect, period of adoption, adjustment	Common stock		Special preferred stock		Capital In Excess of Par Value	Accumulated Income	Accumulated Income Cumulative effect, period of adoption, adjustment	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2018	$ 947,994	$ 4,900	$ 485	[1]	$ 0	[2]	$ 128,448	$ 912,201	$ 4,900	$ (93,140)
Increase (Decrease) in Stockholders' Equity
Net Income (Loss)	36,358							36,358
Dividends declared on common stock ($0.12 per share)	(5,811)							(5,811)
Other comprehensive income, net	2,261									2,261
Issuance of shares of common stock, net of shares withheld for taxes	(982)		1	[1]			(983)
Repurchase and retirement of shares of common stock	(11,086)		(4)	[1]				(11,082)
Share-based compensation expense	1,426						1,426
Ending balance at Mar. 31, 2019	$ 975,060		482	[1]	0	[2]	128,891	936,566		(90,879)
Increase (Decrease) in Stockholders' Equity
Accounting standards update [Extensible List]	us-gaap:AccountingStandardsUpdate201602Member
Beginning balance at Dec. 31, 2018	$ 947,994	$ 4,900	485	[1]	0	[2]	128,448	912,201	$ 4,900	(93,140)
Increase (Decrease) in Stockholders' Equity
Net Income (Loss)	174,267
Other comprehensive income, net	3,027
Ending balance at Sep. 30, 2019	1,066,847		467	[1]	0	[2]	133,003	1,023,490		(90,113)
Beginning balance at Mar. 31, 2019	975,060		482	[1]	0	[2]	128,891	936,566		(90,879)
Increase (Decrease) in Stockholders' Equity
Net Income (Loss)	57,833							57,833
Dividends declared on common stock ($0.12 per share)	(5,743)							(5,743)
Other comprehensive income, net	(2,208)									(2,208)
Issuance of shares of common stock, net of shares withheld for taxes	(32)						(32)
Repurchase and retirement of shares of common stock	(19,604)		(7)	[1]				(19,597)
Share-based compensation expense	1,384						1,384
Ending balance at Jun. 30, 2019	1,006,690		475	[1]	0	[2]	130,243	969,059		(93,087)
Increase (Decrease) in Stockholders' Equity
Net Income (Loss)	80,076							80,076
Dividends declared on common stock ($0.12 per share)	(5,652)							(5,652)
Other comprehensive income, net	2,974									2,974
Issuance of shares of common stock, net of shares withheld for taxes	(13)						(13)
Repurchase and retirement of shares of common stock	(20,001)		(8)	[1]				(19,993)
Share-based compensation expense	2,773						2,773
Ending balance at Sep. 30, 2019	1,066,847		467	[1]	0	[2]	133,003	1,023,490		(90,113)
Beginning balance at Dec. 31, 2019	1,081,796		461	[3]	0	[4]	135,651	1,049,567		(103,883)
Increase (Decrease) in Stockholders' Equity
Net Income (Loss)	(144,372)							(144,372)
Dividends declared on common stock ($0.12 per share)	(5,514)							(5,514)
Other comprehensive income, net	1,331									1,331
Issuance of shares of common stock, net of shares withheld for taxes	(1,230)		1	[3]			(1,231)
Repurchase and retirement of shares of common stock	(7,510)		(2)	[3]				(7,508)
Share-based compensation expense	(135)						(135)
Ending balance at Mar. 31, 2020	924,366		460	[3]	0	[4]	134,285	892,173		(102,552)
Beginning balance at Dec. 31, 2019	1,081,796		461	[3]	0	[4]	135,651	1,049,567		(103,883)
Increase (Decrease) in Stockholders' Equity
Net Income (Loss)	(348,375)
Other comprehensive income, net	(12,416)
Ending balance at Sep. 30, 2020	717,215		460	[3]	0	[4]	144,884	688,170		(116,299)
Beginning balance at Mar. 31, 2020	924,366		460	[3]	0	[4]	134,285	892,173		(102,552)
Increase (Decrease) in Stockholders' Equity
Net Income (Loss)	(106,904)							(106,904)
Other comprehensive income, net	(618)									(618)
Issuance of shares of common stock, net of shares withheld for taxes	(83)		0	[3]			(83)
CARES Act warrant issuance	7,403						7,403
Share-based compensation expense	1,769						1,769
Ending balance at Jun. 30, 2020	825,933		460	[3]	0	[4]	143,374	785,269		(103,170)
Increase (Decrease) in Stockholders' Equity
Net Income (Loss)	(97,099)							(97,099)
Other comprehensive income, net	(13,129)									(13,129)
Issuance of shares of common stock, net of shares withheld for taxes	(45)		0	[3]			(45)
CARES Act warrant issuance	(7)						(7)
Share-based compensation expense	1,562						1,562
Ending balance at Sep. 30, 2020	$ 717,215		$ 460	[3]	$ 0	[4]	$ 144,884	$ 688,170		$ (116,299)

[1] Common Stock—$0.01 par value; 118,000,000 authorized as of September 30, 2019 and December 31, 2018.

[2] Special Preferred Stock—$0.01 par value; 2,000,000 shares authorized as of September 30, 2019 and December 31, 2018.

[3] Common Stock—$0.01 par value; 118,000,000 authorized as of September 30, 2020 and December 31, 2019.

[4] Special Preferred Stock—$0.01 par value; 2,000,000 shares authorized as of September 30, 2020 and December 31, 2019.