Income Tax - Reconciliation of Federal Statutory to Actual Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of Federal Statutory to Actual Tax Expense:
Federal Statutory Income Tax at 21%	$ 50,566	$ 35,695	$ 40,695
Tax-exempt Interest Income	(16,200)	(13,273)	(10,124)
Stock Compensation	(20)	338	(459)
Earnings on Life Insurance	(1,468)	(1,079)	(953)
Tax Credits	(354)	(425)	(263)
CARES Act - NOL carryback rate differential	0	(1,178)	0
State Tax	2,697	1,122	600
Other	38	175	(171)
Income Tax Expense	$ 35,259	$ 21,375	$ 29,325
Effective Tax Rate	14.60%	12.60%	15.10%