Earnings (Loss) Per Share (Computation of Earnings (Loss) Per Common Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Earnings Per Share [Abstract]
Net income (loss) to common shareholders	$ 463,215	$ (45,174)	$ 327,380
Net income or dividends allocated to participating securities - basic and diluted	9,134	1,756	5,546
Net income (loss) allocated to common shareholders - basic and diluted	$ 454,081	$ (46,930)	$ 321,834
Weighted-average common shares - basic	86,823	86,533	86,488
Dilutive potential common shares	204		111
Weighted average common shares - diluted	87,027	86,533	86,599
Earnings (loss) per common share: Basic	$ 5.23	$ (0.54)	$ 3.72
Earnings (loss) per common share: Diluted	$ 5.22	$ (0.54)	$ 3.72