Condensed Consolidated Statement of Shareholders' Equity - USD ($) $ in Thousands	Common stock	Preferred stock 7% Series A Preferred Stock	Preferred stock 6% Series B Preferred Stock	Preferred stock 6% Series C Preferred Stock	Preferred stock 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 (ASU 2016-13) at Dec. 31, 2021						$ (3,648)
Balance at beginning of the period (ASU 2016-02) at Dec. 31, 2021						$ (110)
Balance at beginning of the period at Dec. 31, 2021	$ 137,565	$ 50,221	$ 120,844	$ 191,084			$ 657,149	$ (1,454)
Balance at beginning of the period (in shares) at Dec. 31, 2021	43,180,079	2,081,800	125,000	196,181
Consolidated Statements of Shareholders' Equity
Net income							104,077		$ 104,077
Dividends on 7% preferred stock, annually							(1,821)
Dividends on 6% Series B preferred stock, annually							(3,750)
Dividends on 6% Series C preferred stock, annually							(5,886)
Dividends on common stock, annually							(6,048)
Other comprehensive income (loss)								(6,616)	(6,616)
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	$ 215
Shares issued for stock compensation plans, net of taxes withheld to satisfy tax obligations (in shares)	70,783
Balance at end of the period at Jun. 30, 2022	$ 136,671	$ 50,221	$ 120,844	$ 191,084			737,789	(8,070)	1,228,539
Balance at end of the period (in shares) at Jun. 30, 2022	43,106,505	2,081,800	125,000	196,181
Balance at beginning of the period at Mar. 31, 2022	$ 137,882	$ 50,221	$ 120,844	$ 191,084			694,776	(6,304)
Balance at beginning of the period (in shares) at Mar. 31, 2022	43,267,776	2,081,800	125,000	196,181
Consolidated Statements of Shareholders' Equity
Net income							53,935		53,935
Dividends on 7% preferred stock, annually							(911)
Dividends on 6% Series B preferred stock, annually							(1,875)
Dividends on 6% Series C preferred stock, annually							(2,943)
Dividends on common stock, annually							(3,019)
Other comprehensive income (loss)								(1,766)	(1,766)
Repurchase of common stock	$ (1,761)						(2,174)
Repurchase of common stock (in shares)	(165,037)
Shares issued for stock compensation plans, net of taxes withheld to satisfy tax obligations	$ 550
Shares issued for stock compensation plans, net of taxes withheld to satisfy tax obligations (in shares)	3,766
Balance at end of the period at Jun. 30, 2022	$ 136,671	$ 50,221	$ 120,844	$ 191,084			737,789	(8,070)	1,228,539
Balance at end of the period (in shares) at Jun. 30, 2022	43,106,505	2,081,800	125,000	196,181
Balance at beginning 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 beginning of the period (in shares) at Dec. 31, 2022	43,113,127	2,081,800	125,000	196,181	142,500
Consolidated Statements of Shareholders' Equity
Net income							120,257		120,257
Dividends on 7% preferred stock, annually							(1,821)
Dividends on 6% Series B preferred stock, annually							(3,750)
Dividends on 6% Series C preferred stock, annually							(5,886)
Dividends 8.25 Percent Series D Preferred Stock							(5,878)
Dividends on common stock, annually							(6,918)
Other comprehensive income (loss)								3,485	3,485
Distribution to employee stock ownership plan	$ 810
Distribution to employee stock ownership plan (in shares)	33,293
Shares issued for stock compensation plans, net of taxes withheld to satisfy tax obligations	$ 262
Shares issued for stock compensation plans, net of taxes withheld to satisfy tax obligations (in shares)	90,880
Balance at end of the period at Jun. 30, 2023	$ 138,853	$ 50,221	$ 120,844	$ 191,084	$ 137,459		928,875	(7,036)	1,560,300
Balance at end of the period (in shares) at Jun. 30, 2023	43,237,300	2,081,800	125,000	196,181	142,500
Balance at beginning of the period at Mar. 31, 2023	$ 138,105	$ 50,221	$ 120,844	$ 191,084	$ 137,459		875,700	(7,729)
Balance at beginning of the period (in shares) at Mar. 31, 2023	43,233,618	2,081,800	125,000	196,181	142,500
Consolidated Statements of Shareholders' Equity
Net income							65,302		65,302
Dividends on 7% preferred stock, annually							(911)
Dividends on 6% Series B preferred stock, annually							(1,875)
Dividends on 6% Series C preferred stock, annually							(2,943)
Dividends 8.25 Percent Series D Preferred Stock							(2,939)
Dividends on common stock, annually							(3,459)
Other comprehensive income (loss)								693	693
Shares issued for stock compensation plans, net of taxes withheld to satisfy tax obligations	$ 748
Shares issued for stock compensation plans, net of taxes withheld to satisfy tax obligations (in shares)	3,682
Balance at end of the period at Jun. 30, 2023	$ 138,853	$ 50,221	$ 120,844	$ 191,084	$ 137,459		$ 928,875	$ (7,036)	$ 1,560,300
Balance at end of the period (in shares) at Jun. 30, 2023	43,237,300	2,081,800	125,000	196,181	142,500