Shareholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
	May 03, 2022	Mar. 31, 2022	Mar. 31, 2021
Dividends declared (in dollars per share)		$ 0.53	$ 0.52
Schedule of Accumulated Other Income (Loss) [Abstract]
Balance, Beginning of Period		$ 72,371	$ 335,868
Net change in unrealized gain (loss)		(639,041)	(150,131)
Reclassification Adjustments Included in Earnings [Abstract]
Gain on available for sale securities, net		(937)	(467)
Other comprehensive income, before income taxes		(639,978)	(150,598)
Federal and state income taxes		(149,781)	(36,139)
Other comprehensive income, net of income taxes		(490,197)	(114,459)
Balance, End of Period		(417,826)	221,409
Accumulated Net Unrealized Gain (Loss) on Available for Sale Securities [Member]
Schedule of Accumulated Other Income (Loss) [Abstract]
Balance, Beginning of Period		69,775	335,032
Net change in unrealized gain (loss)		(639,041)	(150,131)
Reclassification Adjustments Included in Earnings [Abstract]
Gain on available for sale securities, net		(937)	(467)
Other comprehensive income, before income taxes		(639,978)	(150,598)
Federal and state income taxes		(149,781)	(36,139)
Other comprehensive income, net of income taxes		(490,197)	(114,459)
Balance, End of Period		(420,422)	220,573
Accumulated Unrealized Gain (Loss) on Employee Benefit Plans [Member]
Schedule of Accumulated Other Income (Loss) [Abstract]
Balance, Beginning of Period		2,596	836
Net change in unrealized gain (loss)		0	0
Reclassification Adjustments Included in Earnings [Abstract]
Gain on available for sale securities, net		0	0
Other comprehensive income, before income taxes		0	0
Federal and state income taxes		0	0
Other comprehensive income, net of income taxes		0	0
Balance, End of Period		$ 2,596	$ 836
Subsequent Event [Member]
Dividends Payable, Date Declared	May 03, 2022
Dividends declared (in dollars per share)	$ 0.53
Dividends Payable, Date to be Paid	May 25, 2022
Dividends Payable, Date of Record	May 10, 2022