Acquisitions - Schedule of Acquisition Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	May 09, 2019	Oct. 12, 2018
Bridgeview Bancorp, Inc.
Assets
Cash and due from banks and interest-bearing deposits in other banks	$ 35,097
Equity securities	6,966
Securities available-for-sale	263,695
Securities held-to-maturity	13,426
FHLB and FRB stock	1,481
Loans	709,889
OREO	6,237
Investment in BOLI	0
Goodwill	57,377
Other intangible assets	15,603
Premises, furniture, and equipment	18,145
Accrued interest receivable and other assets	33,724
Total assets	1,161,640
Liabilities
Noninterest-bearing deposits	179,267
Interest-bearing deposits	807,487
Total deposits	986,754
Borrowed funds	1,746
Senior and subordinated debt	29,360
Accrued interest payable and other liabilities	8,428
Total liabilities	1,026,288
Consideration Paid
Common stock (2019 – 4,728,541, shares issued at $28.61 per share, 2018 – 3,310,912, shares issued at $25.16 per share), net of issuance costs	98,212
Cash paid	37,140
Total consideration paid	$ 135,352
Shares issued (in dollars per share)	$ 28.61
Common stock, shares issued (in shares)	4,728,541
Northern States Financial Corporation
Assets
Cash and due from banks and interest-bearing deposits in other banks		$ 160,145
Equity securities		3,915
Securities available-for-sale		47,149
Securities held-to-maturity		0
FHLB and FRB stock		554
Loans		284,924
OREO		2,549
Investment in BOLI		11,104
Goodwill		30,123
Other intangible assets		12,230
Premises, furniture, and equipment		5,964
Accrued interest receivable and other assets		20,015
Total assets		578,672
Liabilities
Noninterest-bearing deposits		346,714
Interest-bearing deposits		116,446
Total deposits		463,160
Borrowed funds		18,218
Senior and subordinated debt		8,038
Accrued interest payable and other liabilities		5,953
Total liabilities		495,369
Consideration Paid
Common stock (2019 – 4,728,541, shares issued at $28.61 per share, 2018 – 3,310,912, shares issued at $25.16 per share), net of issuance costs		83,303
Cash paid		0
Total consideration paid		$ 83,303
Shares issued (in dollars per share)		$ 25.16
Common stock, shares issued (in shares)		3,310,912