Note 2 - Business Combination	12 Months Ended
Dec. 31, 2019
Notes to Financial Statements
Business Combination Disclosure [Text Block]	NOTE 2 – BUSINESS COMBINATION We completed the merger of Firstbank Corporation (“Firstbank”), a Michigan corporation with approximately $1.5 billion in total assets and 46 branch locations, into Mercantile Bank Corporation as of June 1, 2014 ( “Merger Date”). Each share of Firstbank’s common stock was converted into the right to receive one share of Mercantile common stock, resulting in Mercantile issuing 8,087,272 shares of its common stock. The merger provided an expanded geographic footprint for the Company and increased the size of the balance sheet. The Firstbank transaction was accounted for using the acquisition method of accounting and accordingly, assets acquired, liabilities assumed and consideration exchanged were recorded at estimated fair value on the Merger Date. Goodwill of $49.5 million was calculated as the purchase premium after adjusting for the fair value of net assets acquired and represents the value expected from the synergies created from combining the two banking organizations as well as the economies of scale expected from combining the operations of the two companies. None of the goodwill is deductible for income tax purposes as the merger is accounted for as a tax-free exchange. In most instances, determining the fair value of the acquired assets and assumed liabilities required us to estimate cash flows expected to result from those assets and liabilities and to discount those cash flows at appropriate rates of interest. The most significant of those determinations relates to the valuation of acquired loans. For such loans, the excess of cash flows expected at acquisition over the estimated fair value is recognized as interest income over the remaining lives of the loans. The difference between contractually required payments at acquisition and the cash flows expected to be collected at acquisition reflects the impact of estimated credit losses and other factors, such as prepayments. In accordance with the applicable accounting guidance for business combinations, there was no carry-over of Firstbank’s previously established allowance for loan losses. The acquired loans were divided into loans with evidence of credit quality deterioration, which are accounted for under ASC 310 - 30 (“acquired impaired”), and loans that do not meet this criteria, which are accounted for under ASC 310 - 20 (“acquired non-impaired”). In addition, the loans are further categorized into different loan pools based primarily on the type and purpose of the loan.

NOTE

– BUSINESS COMBINATION

We completed the merger of Firstbank Corporation (“Firstbank”), a Michigan corporation with approximately

$1.5

billion in total assets and

branch locations, into Mercantile Bank Corporation as of

June 1, 2014 (

“Merger Date”). Each share of Firstbank’s common stock was converted into the right to receive

one

share of Mercantile common stock, resulting in Mercantile issuing

8,087,272

shares of its common stock. The merger provided an expanded geographic footprint for the Company and increased the size of the balance sheet.

The Firstbank transaction was accounted for using the acquisition method of accounting and accordingly, assets acquired, liabilities assumed and consideration exchanged were recorded at estimated fair value on the Merger Date. Goodwill of

$49.5

million was calculated as the purchase premium after adjusting for the fair value of net assets acquired and represents the value expected from the synergies created from combining the

two

banking organizations as well as the economies of scale expected from combining the operations of the

two

companies.

None

of the goodwill is deductible for income tax purposes as the merger is accounted for as a tax-free exchange.

In most instances, determining the fair value of the acquired assets and assumed liabilities required us to estimate cash flows expected to result from those assets and liabilities and to discount those cash flows at appropriate rates of interest. The most significant of those determinations relates to the valuation of acquired loans. For such loans, the excess of cash flows expected at acquisition over the estimated fair value is recognized as interest income over the remaining lives of the loans. The difference between contractually required payments at acquisition and the cash flows expected to be collected at acquisition reflects the impact of estimated credit losses and other factors, such as prepayments. In accordance with the applicable accounting guidance for business combinations, there was

carry-over of Firstbank’s previously established allowance for loan losses.

The acquired loans were divided into loans with evidence of credit quality deterioration, which are accounted for under ASC

310

(“acquired impaired”), and loans that do

not

meet this criteria, which are accounted for under ASC

310

(“acquired non-impaired”). In addition, the loans are further categorized into different loan pools based primarily on the type and purpose of the loan.