Premises and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Premises and Equipment
Total, at cost	$ 325,697	$ 336,633
Less accumulated depreciation and amortization	(179,788)	(180,109)
Premises and equipment, net	145,909	156,524
Depreciation and amortization expense	11,600	12,100	$ 11,900
Land and land improvements
Premises and Equipment
Total, at cost	24,368	25,449
Office buildings and improvements
Premises and Equipment
Total, at cost	139,180	152,654
Furniture, fixtures and equipment
Premises and Equipment
Total, at cost	138,590	138,242
Leasehold improvements
Premises and Equipment
Total, at cost	$ 23,559	$ 20,288