Earnings Per Common Share and Stockholders' Equity (Schedule of Earnings Per Common Share, Basic and Diluted) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Earnings Per Share, Basic and Diluted [Line Items]
Net income available to common stockholders - numerator for earnings per common share	$ 555,304	$ 271,765
Weighted average common shares outstanding (shares)	96,866,125	95,734,851
Denominator for earnings per common share - assuming dilution	97,953,313	96,215,665
Earnings per common share	$ 5.73	$ 2.84
Earnings per common share - assuming dilution	$ 5.67	$ 2.82
Stock Options and Deferred Compensation Agreements
Earnings Per Share, Basic and Diluted [Line Items]
Effect of dilutive securities: share-based payment arrangements (shares)	612,265	181,054
Restricted Stock and Restricted Stock Units
Earnings Per Share, Basic and Diluted [Line Items]
Effect of dilutive securities: share-based payment arrangements (shares)	474,923	299,760
Stock Options
Earnings Per Share, Basic and Diluted [Line Items]
Antidilutive securities excluded from computation of diluted earnings per common share, amount (shares)	0	100,000
Antidilutive securities excluded from computation of diluted earnings per common share, exercise price		$ 30.50