Business Combinations - Unaudited Pro Forma Condensed Combined Financial Information (Details) - Blackhawk Bancorp, Inc $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($) $ / shares shares
Business Acquisition [Line Items]
Net interest income	$ 57,640
Provision for credit losses	(402)
Non-interest income	25,664
Non-interest expense	55,808
Income before taxes	27,898
Income tax expense	6,395
Net income	$ 21,503
Earnings per share
Basic | $ / shares	$ 0.9
Diluted | $ / shares	$ 0.9
Basic weighted average shares o/s | shares	23,782,476
Diluted weighted average shares o/s | shares	23,854,194