CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands		Total		Common Stock	Preferred Stock	Capital surplus	Retained earnings		Treasury stock	Accumulated other comprehensive income (loss)
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
Net income		480,711					480,711
Issuance of stock		2,226				2,226
Dividends declared:
Common stock	[2]	(70,048)	[1]				(70,048)
Preferred stock		(706)					(706)
Common stock purchases	[3]	(355,307)				(70,000)			(285,307)
Stock based compensation		14,733				2,899			11,834
Other comprehensive loss, net of tax		(285,682)								(285,682)
Ending balance at Jun. 30, 2021		5,814,614		1,045	22,143	4,506,659	2,670,885		(1,290,427)	(95,691)
Beginning balance at Mar. 31, 2021		5,897,559		1,045	22,143	4,571,919	2,489,453		(1,012,263)	(174,738)
Increase Decrease In Stockholders Equity
Net income		218,079					218,079
Issuance of stock		1,108				1,108
Dividends declared:
Common stock	[1]	(36,294)					(36,294)
Preferred stock		(353)					(353)
Common stock purchases	[3]	(351,365)				(70,000)			(281,365)
Stock based compensation		6,833				3,632			3,201
Other comprehensive loss, net of tax		79,047								79,047
Ending balance at Jun. 30, 2021		5,814,614		1,045	22,143	4,506,659	2,670,885		(1,290,427)	(95,691)
Beginning balance at Dec. 31, 2021		5,969,397		1,046	22,143	4,650,182	2,973,745		(1,352,650)	(325,069)
Increase Decrease In Stockholders Equity
Net income		423,107					423,107
Issuance of stock		2,735				2,735
Dividends declared:
Common stock		(84,195)					(84,195)
Preferred stock		(706)					(706)
Common stock purchases	[4]	(406,295)				(80,000)			(326,295)
Stock based compensation		17,253				3,561			13,692
Other comprehensive loss, net of tax		(1,627,947)								(1,627,947)
Ending balance at Jun. 30, 2022		4,293,349		1,046	22,143	4,576,478	3,311,951		(1,665,253)	(1,953,016)
Beginning balance at Mar. 31, 2022		4,671,246		1,046	22,143	4,571,111	3,143,004		(1,668,820)	(1,397,238)
Increase Decrease In Stockholders Equity
Net income		211,421					211,421
Issuance of stock		1,536				1,536
Dividends declared:
Common stock	[1]	(42,121)					(42,121)	[2]
Preferred stock		(353)					(353)
Common stock purchases		(1,375)							(1,375)
Stock based compensation		8,773				3,831			4,942
Other comprehensive loss, net of tax		(555,778)								(555,778)
Ending balance at Jun. 30, 2022		$ 4,293,349		$ 1,046	$ 22,143	$ 4,576,478	$ 3,311,951		$ (1,665,253)	$ (1,953,016)

[1] Dividends declared per common share during the quarter ended June 30, 2022 - $0.55 (2021 - $0.45).

[2] Dividends declared per common share during the six months ended June 30, 2022 - $1.10 (2021 - $0.85).

[3] During the six month ended June 30, 2021, the Corporation entered into a $350 million accelerated share repurchase transaction with respect to its common stock, which was accounted for as a treasury stock transaction. Refer to Note 17 for additional information.

[4] During the six month ended June 30, 2022, the Corporation entered into a $400 million accelerated share repurchase transaction with respect to its common stock, which was accounted for as a treasury stock transaction. Refer to Note 17 for additional information.