Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net Income
Net income	$ 59,786	$ 55,002	$ 41,162	$ 24,583	$ 30,061	$ 20,259	$ 16,439	$ 10,570	$ 180,533	$ 77,329	$ 62,874
Dividends on preferred stock	(3,618)	(3,618)	(3,619)	(3,618)	(3,618)	(3,022)	(1,743)	(833)	(14,473)	(9,216)	(3,330)
Net Income Allocated to Common Shareholders	$ 56,168	$ 51,384	$ 37,543	$ 20,965	$ 26,443	$ 17,237	$ 14,696	$ 9,737	$ 166,060	$ 68,113	$ 59,544
Weighted-Average Shares
Weighted average shares - Basic									28,742,494	28,705,125	28,692,955
Effect of dilutive securities-restricted stock awards									35,581	40,582	31,464
Weighted average shares - diluted									28,778,075	28,745,707	28,724,419
Per Share Amount
Basic earnings per share	$ 1.95	$ 1.79	$ 1.31	$ 0.73	$ 0.92	$ 0.60	$ 0.51	$ 0.34	$ 5.78	$ 2.37	$ 2.08
Diluted earnings per share	$ 1.95	$ 1.79	$ 1.31	$ 0.73	$ 0.92	$ 0.60	$ 0.51	$ 0.34	$ 5.77	$ 2.37	$ 2.07