CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Cumulative effect adoption adjustment	Common Stock	Preferred Stock	Capital surplus	Retained earnings	Retained earnings Cumulative effect adoption adjustment	Treasury stock	Accumulated other comprehensive income (loss)
Beginning Balance at Dec. 31, 2019	$ 6,016,779	$ (205,842)	$ 1,044	$ 50,160	$ 4,447,412	$ 2,147,915	$ (205,842)	$ (459,814)	$ (169,938)
Increase Decrease In Stockholders Equity [Roll Forward]
Net income	34,302					34,302
Issuance of stock	863				863
Dividends declared:
Common stock	(35,505)					(35,505)
Preferred stock	(700)					(700)
Common stock purchases	(502,801)				(77,066)			(425,735)
Common stock reissuance	3,106				(563)			3,669
Preferred stock redemption	(28,017)			(28,017)
Stock based compensation	6,859				(4,346)			11,205
Other comprehensive loss, net of tax	380,561								380,561
Ending Balance at Mar. 31, 2020	5,669,605		1,044	22,143	4,366,300	1,940,170		(870,675)	210,623
Beginning Balance at Dec. 31, 2020	6,028,687		1,045	22,143	4,571,534	2,260,928		(1,016,954)	189,991
Increase Decrease In Stockholders Equity [Roll Forward]
Net income	262,632					262,632
Issuance of stock	1,118				1,118
Dividends declared:
Common stock	(33,754)					(33,754)
Preferred stock	(353)					(353)
Common stock purchases	(3,942)							(3,942)
Stock based compensation	7,900				(733)			8,633
Other comprehensive loss, net of tax	(364,729)								(364,729)
Ending Balance at Mar. 31, 2021	$ 5,897,559		$ 1,045	$ 22,143	$ 4,571,919	$ 2,489,453		$ (1,012,263)	$ (174,738)