CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]
Total stockholders' equity		$ 36,104	$ 21,724	$ 939,674	$ 1,087,617	$ (40,415)
Balance at beginning of period at Dec. 31, 2018		36,104	21,724	939,674	1,087,617	(40,415)
Common stock withheld for taxes			(17)	(1,865)
Restricted stock grants			26	(26)
Stock-based compensation				1,018
Net income	$ 43,314				43,314
Dividends on common stock					(6,538)
Dividends on preferred stock					(669)
Other comprehensive income, net of tax	20,510					20,510
Balance at end of period at Mar. 31, 2019	2,100,457	36,104	21,733	938,801	1,123,724	(19,905)
Total stockholders' equity	2,100,457	36,104	21,733	938,801	1,123,724	(19,905)
Total stockholders' equity	2,100,457	36,104	21,733	938,801	1,123,724	(19,905)
Total stockholders' equity	2,228,073	36,104	21,736	941,652	1,221,817	6,764
Balance at beginning of period at Dec. 31, 2019	2,228,073	36,104	21,736	941,652	1,221,817	6,764
Common stock withheld for taxes			(5)	(193)
Restricted stock grants			85	(85)
Stock-based compensation				1,142
Net income	2,266				2,266
Dividends on common stock					(10,893)
Dividends on preferred stock					(669)
Other comprehensive income, net of tax	42,352					42,352
Balance at end of period at Mar. 31, 2020	2,199,751	36,104	21,816	942,516	1,150,199	49,116
Total stockholders' equity	2,199,751	36,104	21,816	942,516	1,150,199	49,116
Total stockholders' equity	$ 2,199,751	$ 36,104	$ 21,816	$ 942,516	$ 1,150,199	$ 49,116