Borrowings Textuals (Details) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015	May. 31, 2015	Dec. 31, 2014	Sep. 30, 2014
Borrowings [Line Items]
Proceeds from Federal Home Loan Bank Advances	$ 100,000,000
FHLB Advances, Earliest Period of Maturity in Years	3
FHLB Advances, Furthest Period of Maturity in Years	$ 5
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Weighted Average Interest Rate	1.48%	1.48%
Maximum original maturity term of short-term borrowings		30 days
Long-term Federal Home Loan Bank Advances	$ 181,432,000	$ 181,432,000		$ 0	$ 0
Federal Home Loan Bank, Advances, Weighted Average Interest Rate	1.41%	1.41%
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	$ 1,330,000,000	$ 1,330,000,000
Federal Home Loan Bank, Advances, Maturities Summary, Due in Year Two	7,100,000	7,100,000
Federal Home Loan Bank, Advances, Maturities Summary, Due in Year Three	47,100,000	47,100,000
Federal Home Loan Bank, Advances, Maturities Summary, Due in Year Four	67,100,000	67,100,000
Federal Home Loan Bank, Advances, Maturities Summary, Due in Year Five	100,000	100,000
Federal Home Loan Bank, Advances, Maturities Summary, Floating Rate, after Five Years	60,000,000	60,000,000
Securities Sold under Agreements to Repurchase	23,546,000	23,546,000		0	0
Securities Sold Under Agreements to Repurchase, Maturities Summary, Due Remainder of Current Year	6,000,000	6,000,000
Securities Sold Under Agreements to Repurchase, Maturities, Due in Year Two	5,100,000	5,100,000
Securities Sold Under Agreements to Repurchase, Maturities, Due in Year Three	9,400,000	9,400,000
Securities Sold Under Agreements to Repurchase, Maturities, Due in Year Four	3,100,000	3,100,000
nonrevolving line of credit	$ 25,000,000	$ 25,000,000		0	0
Line of Credit Facility, Interest Rate at Period End	2.209%	2.209%
Trust Preferred Investment Security of Non Public Bank Company			$ 10,000,000	10,000,000
subordinated debt par value	$ 1,000	$ 1,000
Subordinated Debt	$ 18,418,000	$ 18,418,000		$ 0	$ 0
Weighted-average interest rate, subordinated debt instruments	4.44%	4.44%
Lake Michigan Financial Corp [Member]
Borrowings [Line Items]
Long-term Federal Home Loan Bank Advances			81,500,000
Securities Sold under Agreements to Repurchase			$ 23,700,000
LMFCTI [Member]
Borrowings [Line Items]
Subordinated Debt	$ 10,300,000	$ 10,300,000
Subordinated Borrowing, Interest Rate		3.45%
Debt Instrument, Interest Rate, Effective Percentage	3.78%	3.78%
LMFCTII [Member]
Borrowings [Line Items]
Subordinated Debt	$ 8,200,000	$ 8,200,000
Subordinated Borrowing, Interest Rate		2.70%
Debt Instrument, Interest Rate, Effective Percentage	3.03%	3.03%