Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Impact of adoption of ASU No. 2016-13	Balance, January 1, 2020 after adoption of ASU No. 2016-13	Common stock	Common stock Balance, January 1, 2020 after adoption of ASU No. 2016-13	Retained earnings	Retained earnings Impact of adoption of ASU No. 2016-13	Retained earnings Balance, January 1, 2020 after adoption of ASU No. 2016-13	Accumulated other comprehensive income (loss)	Accumulated other comprehensive income (loss) Balance, January 1, 2020 after adoption of ASU No. 2016-13
Beginning balance (in shares) at Dec. 31, 2018				108,879,000
Beginning balance at Dec. 31, 2018	$ 2,162,280			$ 1,669,267		$ 543,623			$ (50,610)
Increase (decrease) in stockholders' equity
Net income for common stock	217,882					217,882
Other comprehensive income (loss), net of taxes (benefits)	30,571								30,571
Issuance of common stock:
Share-based plans (in shares)				94,000
Share-based plans	3,092			$ 3,092
Share-based expenses and other, net	5,898			$ 5,898
Common stock dividends	(139,463)					(139,463)
Ending balance (in shares) at Dec. 31, 2019				108,973,000	108,973,000
Ending balance at Dec. 31, 2019	$ 2,280,260	$ (15,372)	$ 2,264,888	$ 1,678,257	$ 1,678,257	622,042	$ (15,372)	$ 606,670	(20,039)	$ (20,039)
Issuance of common stock:
Accounting standards update, extensible Llist	Accounting Standards Update 2016-13 [Member]
Net income for common stock	$ 197,824					197,824
Other comprehensive income (loss), net of taxes (benefits)	18,775								18,775
Share-based plans (in shares)				208,000
Share-based plans	3,973			$ 3,973
Share-based expenses and other, net	(3,862)			$ (3,862)
Common stock dividends	$ (144,096)					(144,096)
Ending balance (in shares) at Dec. 31, 2020	109,181,124			109,181,000
Ending balance at Dec. 31, 2020	$ 2,337,502			$ 1,678,368		660,398			(1,264)
Increase (decrease) in stockholders' equity
Net income for common stock	246,166					246,166
Other comprehensive income (loss), net of taxes (benefits)	(51,269)								(51,269)
Issuance of common stock:
Share-based plans (in shares)				131,000
Share-based plans	5,027			$ 5,027
Share-based expenses and other, net	2,101			$ 2,101
Common stock dividends	$ (148,643)					(148,643)
Ending balance (in shares) at Dec. 31, 2021	109,311,785			109,312,000
Ending balance at Dec. 31, 2021	$ 2,390,884			$ 1,685,496		$ 757,921			$ (52,533)