Consolidated Statement of Shareholders' Equity - USD ($) $ in Thousands	Common stock		Preferred stock 8% Preferred Stock	Preferred stock 7% Series A Preferred Stock	Preferred stock 6% Series B Preferred Stock	Preferred stock 6% Series C Preferred Stock Public Offering	Preferred stock 6% Series C Preferred Stock Private Placement	Preferred stock 6% Series C Preferred Stock	Preferred stock 8.25% Series D Preferred Stock	Retained Earnings 6% Series B Preferred Stock	Retained Earnings 6% Series C Preferred Stock	Retained Earnings 8.25% Series D Preferred Stock	Retained Earnings Impact from adoption of ASU	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Total
Balance at beginning of the period at Dec. 31, 2019	$ 135,640	[1]	$ 41,581											$ 304,984	$ 458
Balance at beginning of the period (in shares) at Dec. 31, 2019	43,059,657	[1]	41,625
Consolidated Statements of Shareholders' Equity
Net income														180,533		$ 180,533
Treasury shares constructively retired	$ (150)													(102)
Treasury shares constructively retired (in shares)	(22,500)
Dividends on 8% preferred stock, annually														(3,330)
Dividends on 7% preferred stock, annually														(3,643)
Dividends on 6% preferred stock, annually										$ (7,500)
Dividends on common stock, annually														(9,198)
Other comprehensive loss															(84)	(84)
Shares issued for stock compensation plans, net of taxes withheld to satisfy tax obligations	$ 367
Shares issued for stock compensation plans, net of taxes withheld to satisfy tax obligations (in shares)	83,468
Balance at end of the period at Dec. 31, 2020	$ 135,857	[1]	$ 41,581	$ 50,221	$ 120,844									461,744	374	810,621
Balance at end of the period (in shares) at Dec. 31, 2020	43,120,625	[1]	41,625	2,081,800	125,000
Consolidated Statements of Shareholders' Equity
Net income														227,104		227,104
Issuance of shares, net of offering expenses						$ 144,926	$ 46,158
Issuance of shares, net of offering expenses (in shares)						150,000	46,181
Dividends on 8% preferred stock, annually														(833)
Final dividend for redemption of 8% preferred stock														(139)
Dividends on 7% preferred stock, annually														(3,643)
Dividends on 6% preferred stock, annually										(7,500)	$ (8,758)
Dividends on common stock, annually														(10,362)
Deconsolidation of entities														(419)
Other comprehensive loss															(1,828)	$ (1,828)
Redemption of 8% preferred stock			$ (41,581)											(45)
Redemption of 8% preferred stock (in shares)			(41,625)
Repurchase of common stock (in shares)																0
Distribution to employee stock ownership plan	$ (537)
Distribution to employee stock ownership plan (in shares)	(29,149)
Shares issued for stock compensation plans, net of taxes withheld to satisfy tax obligations	$ 1,171
Shares issued for stock compensation plans, net of taxes withheld to satisfy tax obligations (in shares)	30,305
Balance at end of the period at Dec. 31, 2021	$ 137,565	[1]		$ 50,221	$ 120,844			$ 191,084						657,149	(1,454)	$ 1,155,409
Balance at end of the period (in shares) at Dec. 31, 2021	43,180,079	[1]		2,081,800	125,000			196,181
Consolidated Statements of Shareholders' Equity
Net income														219,721		219,721
Issuance of shares, net of offering expenses									$ 137,459
Issuance of shares, net of offering expenses (in shares)									142,500
Dividends on 7% preferred stock, annually														(3,643)
Dividends on 6% preferred stock, annually										$ (7,500)	$ (11,772)
Dividends 8.25 Percent Series D Preferred Stock												$ (3,068)
Dividends on common stock, annually														(12,084)
Other comprehensive loss															(9,067)	(9,067)
Repurchase of common stock	$ (1,761)													(2,174)
Repurchase of common stock (in shares)	(165,037)
Cash paid in lieu of fractional shares for stock split	$ (1)
Cash paid in lieu of fractional shares for stock split (in shares)	(29)
Distribution to employee stock ownership plan	$ (653)
Distribution to employee stock ownership plan (in shares)	(20,709)
Shares issued for stock compensation plans, net of taxes withheld to satisfy tax obligations	$ 1,325
Shares issued for stock compensation plans, net of taxes withheld to satisfy tax obligations (in shares)	77,405
Balance at end of the period (ASU 2016-13) at Dec. 31, 2022													$ (3,648)
Balance at end of the period (ASU 2016-02) at Dec. 31, 2022													$ (110)
Balance at end of the period at Dec. 31, 2022	$ 137,781			$ 50,221	$ 120,844			$ 191,084	$ 137,459					$ 832,871	$ (10,521)	$ 1,459,739
Balance at end of the period (in shares) at Dec. 31, 2022	43,113,127			2,081,800	125,000			196,181	142,500

[1] The number of shares have been restated to reflect the 3-for-2 common stock split, effective on January 17, 2022.