Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock Outstanding	Common Stock	Value of Shares Held in Rabbi Trust at Cost	Deferred Compensation and Other Retirement Benefit Obligations	Additional Paid in Capital	Retained Earnings	Accumulated Other Comprehensive Income/(Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Shares, Outstanding		47,349,778
Net income	$ 53,097						$ 53,097
Other comprehensive income	(80,385)							$ (80,385)
Cash dividends declared per common share (in dollars per share)							$ 0.51
Common dividend declared	(24,162)						$ (24,162)
Stock based compensation	834					$ 834
Restricted stock awards issued, net of awards surrendered		44,569
Restricted stock awards issued, net of awards surrendered	(1,063)		$ 0			(1,063)
Shares issued under direct stock purchase plan		6,602
Shares issued under direct stock purchase plan	571		0			571
Stock Repurchased During Period, Shares		(23,824)
Stock Repurchased During Period, Value	(1,902)					(1,902)
Increase (Decrease) in Deferred Compensation and Other Retirement Benefits				$ (33)	$ 33
Increase (Decrease) in Deferred Compensation	0
Period End Balance at Mar. 31, 2022	$ 2,965,439		472	(3,179)	3,179	2,247,518	795,651	(78,202)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Shares, Outstanding		47,377,125
Common Stock, Shares, Outstanding	45,641,238	45,641,238
Net income	$ 61,247						$ 61,247
Other comprehensive income	27,139							27,139
Cash dividends declared per common share (in dollars per share)							$ 0.55
Common dividend declared	(24,351)						$ (24,351)
Proceeds from exercise of stock options, net of cash paid		1,666
Stock Repurchased During Period, Value, as a result of Stock Options Exercised	80					80
Stock based compensation	1,672					1,672
Restricted stock awards issued, net of awards surrendered		81,075
Restricted stock awards issued, net of awards surrendered	(1,110)					(1,110)
Shares issued under direct stock purchase plan		7,881
Shares issued under direct stock purchase plan	642					642
Stock Repurchased During Period, Shares		(1,617,033)
Stock Repurchased During Period, Value	(121,111)		(16)			(121,095)
Increase (Decrease) in Deferred Compensation and Other Retirement Benefits				(59)	59
Increase (Decrease) in Deferred Compensation	0
Period End Balance at Mar. 31, 2023	$ 2,830,909		$ 439	$ (3,286)	$ 3,286	$ 1,995,077	$ 971,338	$ (135,945)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Shares, Outstanding	44,114,827	44,114,827
Sales and Excise Tax Payable	$ 1,200