Consolidated Statements of Changes In Stockholders' Equity - USD ($) $ in Thousands	Total	Adjustment to apply recent accounting pronouncements	[1]	Common Shares Outstanding	Preferred Stock	Additional Paid-in Capital	Retained Earnings	Retained Earnings Adjustment to apply recent accounting pronouncements	[1]	Total Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Beginning balance (in shares) at Dec. 31, 2019				109,972,000
Beginning balance at Dec. 31, 2019	$ 2,370,793	$ (26,821)		$ 1,204	$ 0	$ 1,211,274	$ 1,380,612	$ (26,821)		$ (1,954)	$ (220,343)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	38,670						38,670
Other comprehensive income (loss)	30,681									30,681
Preferred dividends	(1,037)						(1,037)
Common dividends declared	(32,017)						(32,017)
Repurchases of common stock (in shares)				(1,171,000)
Repurchases of common stock	(22,557)										(22,557)
Acquisitions, net of issuance costs (in shares)				4,930,000
Acquisition, net of issuance costs	71,883			$ 49		71,834
Preferred stock issued	221,312				230,500	(9,188)
Common stock issued (in shares)				43,000
Common stock issued	930					251					679
Restricted stock activity (in shares)				513,000
Restricted stock activity	(3,135)					(13,180)					10,045
Treasury stock issued to benefit plans (in shares)				(11,000)
Treasury stock issued to benefit plans	(168)					(21)					(147)
Share-based compensation expense	7,677					7,677
Ending balance (in shares) at Jun. 30, 2020				114,276,000
Ending balance at Jun. 30, 2020	2,656,211			$ 1,253	230,500	1,268,647	1,359,407			28,727	(232,323)
Beginning balance (in shares) at Mar. 31, 2020				114,213,000
Beginning balance at Mar. 31, 2020	2,435,707			$ 1,253	0	1,274,935	1,357,395			35,323	(233,199)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	19,064						19,064
Other comprehensive income (loss)	(6,596)									(6,596)
Preferred dividends	(1,037)						(1,037)
Common dividends declared	(16,015)						(16,015)
Preferred stock issued	221,312				230,500	(9,188)
Common stock issued (in shares)				6,000
Common stock issued	79					79
Restricted stock activity (in shares)				64,000
Restricted stock activity	31					(912)					943
Treasury stock issued to benefit plans (in shares)				(7,000)
Treasury stock issued to benefit plans	(89)					(22)					(67)
Share-based compensation expense	3,755					3,755
Ending balance (in shares) at Jun. 30, 2020				114,276,000
Ending balance at Jun. 30, 2020	$ 2,656,211			$ 1,253	230,500	1,268,647	1,359,407			28,727	(232,323)
Beginning balance (in shares) at Dec. 31, 2020	114,296,000			114,296,000
Beginning balance at Dec. 31, 2020	$ 2,690,006			$ 1,254	230,500	1,275,492	1,388,525			26,379	(232,144)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	96,144						96,144
Other comprehensive income (loss)	(32,320)									(32,320)
Preferred dividends	(8,068)						(8,068)
Common dividends declared	(31,976)						(31,976)
Repurchases of common stock (in shares)				(715,000)
Repurchases of common stock	(14,929)										(14,929)
Acquisition, net of issuance costs	0
Common stock issued (in shares)				69,000
Common stock issued	1,099			$ 0		56					1,043
Restricted stock activity (in shares)				526,000
Restricted stock activity	(4,002)					(14,534)					10,532
Treasury stock issued to benefit plans (in shares)				1,000
Treasury stock issued to benefit plans	37					21					16
Share-based compensation expense	$ 8,157					8,157
Ending balance (in shares) at Jun. 30, 2021	114,177,000			114,177,000
Ending balance at Jun. 30, 2021	$ 2,704,148			$ 1,254	230,500	1,269,192	1,444,625			(5,941)	(235,482)
Beginning balance (in shares) at Mar. 31, 2021				114,196,000
Beginning balance at Mar. 31, 2021	2,653,315			$ 1,254	230,500	1,265,156	1,413,517			(22,096)	(235,016)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	51,121						51,121
Other comprehensive income (loss)	16,155									16,155
Preferred dividends	(4,034)						(4,034)
Common dividends declared	(15,979)						(15,979)
Repurchases of common stock	0
Common stock issued (in shares)				4,000
Common stock issued	83					83
Restricted stock activity (in shares)				(22,000)
Restricted stock activity	(105)					347					(452)
Treasury stock issued to benefit plans (in shares)				(1,000)
Treasury stock issued to benefit plans	(16)					(2)					(14)
Share-based compensation expense	$ 3,608					3,608
Ending balance (in shares) at Jun. 30, 2021	114,177,000			114,177,000
Ending balance at Jun. 30, 2021	$ 2,704,148			$ 1,254	$ 230,500	$ 1,269,192	$ 1,444,625			$ (5,941)	$ (235,482)

[1] As a result of accounting guidance adopted in the first quarter of 2020, a portion of the increase in allowance for credit losses, net of tax, was recognized as a cumulative-effect adjustment to retained earnings as of January 1, 2020.