Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Common stock	Retained earnings	Accumulated other comprehensive income (loss)
Beginning balance (in shares) at Dec. 31, 2020		109,181,000
Beginning 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	(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		109,312,000
Ending balance at Dec. 31, 2021	2,390,884	$ 1,685,496	757,921	(52,533)
Increase (decrease) in stockholders' equity
Net income for common stock	241,138		241,138
Other comprehensive income (loss), net of taxes	(283,495)			(283,495)
Issuance of common stock:
Share-based plans (in shares)		159,000
Share-based plans	5,831	$ 5,831
Share-based expenses and other, net	1,370	$ 1,370
Common stock dividends	$ (153,229)		(153,229)
Ending balance (in shares) at Dec. 31, 2022	109,470,795	109,471,000
Ending balance at Dec. 31, 2022	$ 2,202,499	$ 1,692,697	845,830	(336,028)
Increase (decrease) in stockholders' equity
Net income for common stock	199,238		199,238
Other comprehensive income (loss), net of taxes	46,678			46,678
Issuance of common stock:
Dividend reinvestment and stock purchase plan (in shares)		537,000
Dividend reinvestment and stock purchase plan	6,612	$ 6,612
Share-based plans (in shares)		144,000
Share-based plans	6,371	$ 6,371
Share-based expenses and other, net	1,791	$ 1,791
Common stock dividends	$ (118,348)		(118,348)
Ending balance (in shares) at Dec. 31, 2023	110,151,798	110,152,000
Ending balance at Dec. 31, 2023	$ 2,344,841	$ 1,707,471	$ 926,720	$ (289,350)