CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Impact of ASU 2016-13 adoption	Preferred Stock	Common Stock	Capital Surplus	Retained Earnings	Retained Earnings Impact of ASU 2016-13 adoption	Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment from the adoption of ASU 2016-02		$ (1,713)					$ (1,713)
Balance at beginning of period at Dec. 31, 2018	$ 1,325,175		$ 0	$ 34,477	$ 743,095	$ 579,252		$ (31,649)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	113,454					76,666		36,788
Cash dividends declared:
Common	(11,397)					(11,397)
Issuance of shares of common stock	92,666			2,213	90,453
Stock based compensation	3,602				3,602
Balance at end of period at Jun. 30, 2019	1,521,787		0	36,690	837,150	642,808		5,139
Balance at beginning of period at Mar. 31, 2019	1,372,102		0	34,604	745,596	603,506		(11,604)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	61,912					45,169		16,743
Cash dividends declared:
Common	(5,867)					(5,867)
Issuance of shares of common stock	92,413			2,086	90,327
Stock based compensation	1,227				1,227
Balance at end of period at Jun. 30, 2019	1,521,787		0	36,690	837,150	642,808		5,139
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment from the adoption of ASU 2016-02		$ (14,891)					$ (14,891)
Balance at beginning of period at Dec. 31, 2019	1,578,137		0	36,704	839,857	702,502		(926)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	83,655					50,171		33,484
Cash dividends declared:
Common	(14,715)					(14,715)
Issuance of shares of preferred stock	110,705		110,705
Issuance of shares of common stock	928			141	787
Stock based compensation	3,558				3,558
Balance at end of period at Jun. 30, 2020	1,747,377		110,705	36,845	844,202	723,067		32,558
Balance at beginning of period at Mar. 31, 2020	1,553,714		0	36,807	842,780	700,298		(26,171)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	88,860					30,131		58,729
Cash dividends declared:
Common	(7,362)					(7,362)
Issuance of shares of preferred stock	110,705		110,705
Issuance of shares of common stock	124			38	86
Stock based compensation	1,336				1,336
Balance at end of period at Jun. 30, 2020	$ 1,747,377		$ 110,705	$ 36,845	$ 844,202	$ 723,067		$ 32,558