XML 59 R43.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Note 12 - Stock-based Compensation (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2019
Notes Tables |
Share-based Payment Arrangement, Restricted Stock Unit, Activity [Table Text Block] |
|  | 2019 |  |  | 2018 |  |  | 2017 |
|  | Shares |  |  | Weighted Average Fair Value |  |  | Shares |  |  | Weighted Average Fair Value |  |  | Shares |  |  | Weighted Average Fair Value |
Nonvested at beginning of year |  |  | 262,967 |  |  | $ | 33.97 |  |  |  | 239,637 |  |  | $ | 32.37 |  |  |  | 228,343 |  |  | $ | 26.09 |
Granted |  |  | 84,596 |  |  |  | 35.29 |  |  |  | 91,400 |  |  |  | 31.82 |  |  |  | 94,592 |  |  |  | 37.11 |
Vested |  |  | (81,772 | ) |  |  | 32.19 |  |  |  | (55,792 | ) |  |  | 25.14 |  |  |  | (74,979 | ) |  |  | 20.17 |
Forfeited |  |  | (3,531 | ) |  |  | 34.85 |  |  |  | (12,278 | ) |  |  | 31.62 |  |  |  | (8,319 | ) |  |  | 23.75 |
Nonvested at end of year |  |  | 262,260 |  |  | $ | 34.91 |  |  |  | 262,967 |  |  | $ | 33.97 |  |  |  | 239,637 |  |  | $ | 32.37 |
Share-based Payment Arrangement, Option, Activity [Table Text Block] |
|  | 2019 |  |  | 2018 |  |  | 2017 |
|  | Shares |  |  | Weighted Average Exercise Price |  |  | Shares |  |  | Weighted Average Exercise Price |  |  | Shares |  |  | Weighted Average Exercise Price |
Outstanding at beginning of year |  |  | 13,700 |  |  | $ | 30.51 |  |  |  | 15,808 |  |  | $ | 29.62 |  |  |  | 16,808 |  |  | $ | 29.17 |
Granted |  |  | 0 |  |  | NA |  |  |  | 0 |  |  | NA |  |  |  | 0 |  |  | NA |
Exercised |  |  | (4,000 | ) |  |  | 24.91 |  |  |  | (2,108 | ) |  |  | 23.77 |  |  |  | (1,000 | ) |  |  | 22.15 |
Forfeited or expired |  |  | 0 |  |  | NA |  |  |  | 0 |  |  | NA |  |  |  | 0 |  |  | NA |
Outstanding at end of year |  |  | 9,700 |  |  | $ | 32.83 |  |  |  | 13,700 |  |  | $ | 30.51 |  |  |  | 15,808 |  |  | $ | 29.62 |
Options exercisable at year-end |  |  | 9,700 |  |  | $ | 32.83 |  |  |  | 13,700 |  |  | $ | 30.51 |  |  |  | 9,308 |  |  | $ | 25.00 |
|  | 2019 |  |  | 2018 |  |  | 2017 |
|  | Shares |  |  | Weighted Average Exercise Price |  |  | Shares |  |  | Weighted Average Exercise Price |  |  | Shares |  |  | Weighted Average Exercise Price |
Outstanding at beginning of year |  |  | 5,200 |  |  | $ | 6.57 |  |  |  | 15,100 |  |  | $ | 7.20 |  |  |  | 44,275 |  |  | $ | 9.86 |
Granted |  |  | 0 |  |  | NA |  |  |  | 0 |  |  | NA |  |  |  | 0 |  |  | NA |
Exercised |  |  | (4,200 | ) |  |  | 6.90 |  |  |  | (9,900 | ) |  |  | 7.53 |  |  |  | (27,675 | ) |  |  | 11.50 |
Forfeited or expired |  |  | 0 |  |  | NA |  |  |  | 0 |  |  | NA |  |  |  | (1,500 | ) |  |  | 6.33 |
Outstanding at end of year |  |  | 1,000 |  |  | $ | 5.19 |  |  |  | 5,200 |  |  | $ | 6.57 |  |  |  | 15,100 |  |  | $ | 7.20 |
Options exercisable at year-end |  |  | 1,000 |  |  | $ | 5.19 |  |  |  | 5,200 |  |  | $ | 6.57 |  |  |  | 15,100 |  |  | $ | 7.20 |
Share-based Payment Arrangement, Option, Exercise Price Range [Table Text Block] |
|  |  |  |  | Outstanding |  |  | Exercisable |
|  |  |  |  |  |  |  |  | Weighted Average |  |  | Weighted |  |  |  |  |  |  | Weighted |
Range of |  |  |  |  |  |  | Remaining |  |  | Average |  |  |  |  |  |  | Average |
Exercise |  |  |  |  |  |  | Contractual |  |  | Exercise |  |  |  |  |  |  | Exercise |
Prices |  |  | Number |  |  | Life (Years) |  |  | Price |  |  | Number |  |  | Price |
$22.00 | - | $23.00 |  |  |  | 1,000 |  |  | 1.9 |  |  | $ | 22.15 |  |  |  | 1,000 |  |  |  | 22.15 |
$27.00 | - | $28.00 |  |  |  | 2,200 |  |  | 2.9 |  |  |  | 27.66 |  |  |  | 2,200 |  |  |  | 27.66 |
$36.00 | - | $37.00 |  |  |  | 6,500 |  |  | 3.9 |  |  |  | 36.22 |  |  |  | 6,500 |  |  |  | 36.22 |
Outstanding at year end |  |  | 9,700 |  |  | 3.4 |  |  | $ | 32.83 |  |  |  | 9,700 |  |  |  | 32.83 |
|  |  |  |  | Outstanding |  |  | Exercisable |
|  |  |  |  |  |  |  |  | Weighted Average |  |  | Weighted |  |  |  |  |  |  | Weighted |
Range of |  |  |  |  |  |  | Remaining |  |  | Average |  |  |  |  |  |  | Average |
Exercise |  |  |  |  |  |  | Contractual |  |  | Exercise |  |  |  |  |  |  | Exercise |
Prices |  |  | Number |  |  | Life (Years) |  |  | Price |  |  | Number |  |  | Price |
$ 5.00 | - | $ 6.00 |  |  |  | 1,000 |  |  | 0.9 |  |  |  | 5.19 |  |  |  | 1,000 |  |  |  | 5.19 |
Outstanding at year end |  |  | 1,000 |  |  | 0.9 |  |  | $ | 5.19 |  |  |  | 1,000 |  |  | $ | 5.19 |
Schedule of Share-based Compensation Shares Authorized Under Stock Option Plans Information Related to Option Outstanding [Table Text Block] |
|  | 2019 |  |  | 2018 |  |  | 2017 |
Minimum exercise price |  | $ | 22.15 |  |  | $ | 22.15 |  |  | $ | 22.15 |
Maximum exercise price |  |  | 36.22 |  |  |  | 36.22 |  |  |  | 36.22 |
Average remaining option term (years) |  |  | 3.4 |  |  |  | 4.1 |  |  |  | 5.0 |
|  | 2019 |  |  | 2018 |  |  | 2017 |
Minimum exercise price |  | $ | 5.19 |  |  | $ | 5.19 |  |  | $ | 5.19 |
Maximum exercise price |  |  | 5.19 |  |  |  | 8.60 |  |  |  | 8.60 |
Average remaining option term (years) |  |  | 0.9 |  |  |  | 1.5 |  |  |  | 1.7 |
Schedule of Share Based Compensation Arrangement by Share Based Payment Award Options Information Related to Stock Option Grants and Exercised [Table Text Block] |
|  | 2019 |  |  | 2018 |  |  | 2017 |
Aggregate intrinsic value of stock options exercised |  | $ | 43,000 |  |  | $ | 17,000 |  |  | $ | 15,000 |
Cash received from stock option exercises |  |  | 97,000 |  |  |  | 33,000 |  |  |  | 0 |
Tax benefit realized from stock option exercises |  |  | 0 |  |  |  | 0 |  |  |  | 0 |
Weighted average per share fair value of stock options granted |  | NA |  |  | NA |  |  | NA |
|  | 2019 |  |  | 2018 |  |  | 2017 |
Aggregate intrinsic value of stock options exercised |  | $ | 114,000 |  |  | $ | 300,000 |  |  | $ | 594,000 |
Cash received from stock option exercises |  |  | 29,000 |  |  |  | 108,000 |  |  |  | 318,000 |
Tax benefit realized from stock option exercises |  |  | 0 |  |  |  | 0 |  |  |  | 208,000 |
Weighted average per share fair value of stock options granted |  | NA |  |  | NA |  |  | NA |

X
- Definition Schedule of share based compensation arrangement by share based payment award options information related to stock option grants and exercised. + References No definition available. + Details
Name: | mbwm_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsInformationRelatedToStockOptionGrantsAndExercisedTableTextBlock
Namespace Prefix: | mbwm_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Schedule of share based compensation shares authorized under stock option plans information related to option outstanding. + References No definition available. + Details
Name: | mbwm_ScheduleOfSharebasedCompensationSharesAuthorizedUnderStockOptionPlansInformationRelatedToOptionOutstandingTableTextBlock
Namespace Prefix: | mbwm_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the number and weighted-average grant date fair value for restricted stock units that were outstanding at the beginning and end of the year, and the number of restricted stock units that were granted, vested, or forfeited during the year. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
Name: | us-gaap_ScheduleOfShareBasedCompensationRestrictedStockUnitsAwardActivityTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of option exercise prices, by grouped ranges, including the upper and lower limits of the price range, the number of shares under option, weighted average exercise price and remaining contractual option terms. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
Name: | us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure for stock option plans. Includes, but is not limited to, outstanding awards at beginning and end of year, grants, exercises, forfeitures, and weighted-average grant date fair value. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
Name: | us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_TableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration