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Note 12 - Stock-based Compensation (Tables) | 12 Months Ended
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Dec. 31, 2014
Note 12 - Stock-based Compensation (Tables) [Line Items] |
Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block] |
|  | 2014 |  |  | 2013 |  |  | 2012 |
|  |  |  |  |  | Weighted |  |  |  |  |  |  | Weighted |  |  |  |  |  |  | Weighted |
|  |  |  |  |  | Average |  |  |  |  |  |  | Average |  |  |  |  |  |  | Average |
|  | Shares |  |  | Fair Value |  |  | Shares |  |  | Fair Value |  |  | Shares |  |  | Fair Value |
Nonvested at beginning of year |  |  | 63,800 |  |  | $ | 14.30 |  |  |  | 66,100 |  |  | $ | 14.30 |  |  |  | 38,650 |  |  | $ | 6.20 |
Granted |  |  | 101,490 |  |  |  | 20.13 |  |  |  | 0 |  |  | NA |  |  |  | 66,100 |  |  |  | 14.30 |
Vested |  |  | (63,300 | ) |  |  | 14.30 |  |  |  | 0 |  |  | NA |  |  |  | (38,266 | ) |  |  | 6.20 |
Forfeited |  |  | (500 | ) |  |  | 14.30 |  |  |  | (2,300 | ) |  |  | 14.30 |  |  |  | (384 | ) |  |  | 6.20 |
Nonvested at end of year |  |  | 101,490 |  |  | $ | 20.13 |  |  |  | 63,800 |  |  | $ | 14.30 |  |  |  | 66,100 |  |  | $ | 14.30 |
Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block] |
|  | 2014 |  |  | 2013 |  |  | 2012 |
|  |  |  |  |  | Weighted |  |  |  |  |  |  | Weighted |  |  |  |  |  |  | Weighted |
|  |  |  |  |  | Average |  |  |  |  |  |  | Average |  |  |  |  |  |  | Average |
|  |  |  |  |  | Exercise |  |  |  |  |  |  | Exercise |  |  |  |  |  |  | Exercise |
|  | Shares |  |  | Price |  |  | Shares |  |  | Price |  |  | Shares |  |  | Price |
Outstanding at beginning of year |  |  | 60,876 |  |  | $ | 33.11 |  |  |  | 152,896 |  |  | $ | 26.15 |  |  |  | 214,903 |  |  | $ | 22.40 |
Granted |  |  | 6,488 |  |  |  | 22.15 |  |  |  | 0 |  |  | NA |  |  |  | 0 |  |  | NA |
Exercised |  |  | (2,845 | ) |  |  | 17.74 |  |  |  | (51,055 | ) |  |  | 13.72 |  |  |  | (50,930 | ) |  |  | 10.83 |
Forfeited or expired |  |  | (29,184 | ) |  |  | 34.60 |  |  |  | (40,965 | ) |  |  | 31.30 |  |  |  | (11,077 | ) |  |  | 23.77 |
Outstanding at end of year |  |  | 35,335 |  |  | $ | 31.09 |  |  |  | 60,876 |  |  | $ | 33.11 |  |  |  | 152,896 |  |  | $ | 26.15 |
Options exercisable at year-end |  |  | 28,847 |  |  | $ | 33.11 |  |  |  | 60,876 |  |  | $ | 33.11 |  |  |  | 152,896 |  |  | $ | 26.15 |
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] |
|  | 2014 |
Risk-free interest rate |  |  | 1.56 | %
Expected option life (Years) |  |  | 5 |
Expected stock price volatility |  |  | 26 | %
Dividend yield |  |  | 2.5 | %
Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by 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 |
$6.21 | - | $ 8.00 |  |  |  | 2,700 |  | 0.9 |  | $ | 6.21 |  |  |  | 2,700 |  |  | $ | 6.21 |
$20.01 | - | $24.00 |  |  |  | 6,488 |  | 6.9 |  |  | 22.15 |  |  |  | 0 |  |  | NA |
$32.01 | - | $36.00 |  |  |  | 26,147 |  | 0.9 |  |  | 35.88 |  |  |  | 26,147 |  |  |  | 35.88 |
Outstanding at year end |  |  |  | 35,335 |  | 2.0 |  | $ | 31.09 |  |  |  | 28,847 |  |  | $ | 33.11 |
|  |  |  |  | Outstanding |  |  | Exercisable |
|  |  |  |  |  |  |  | Weighted Average |  | Weighted |  |  |  |  |  |  | Weighted |
Range of |  |  |  |  |  | Remaining |  | Average |  |  |  |  |  |  | Average |
Exercise |  |  |  |  |  | Contractual |  | Exercise |  |  |  |  |  |  | Exercise |
Prices |  |  | Number |  | Life (Years) |  | Price |  |  | Number |  |  | Price |
$4.00 | - | $8.00 |  |  |  | 63,590 |  | 4.9 |  | $ | 6.53 |  |  |  | 56,385 |  |  | $ | 6.70 |
$8.01 | - | $12.00 |  |  |  | 68,430 |  | 3.7 |  |  | 13.20 |  |  |  | 68,430 |  |  |  | 13.20 |
$20.01 | - | $25.00 |  |  |  | 85,962 |  | 1.4 |  |  | 22.43 |  |  |  | 85,962 |  |  |  | 22.43 |
Outstanding at year end |  |  |  | 217,982 |  | 3.1 |  | $ | 14.89 |  |  |  | 210,777 |  |  | $ | 15.22 |
Schedule of Share-based Compensation Shares Authorized under Stock Option Plans Information Related to Option Outstanding [Table Text Block] |
|  | 2014 |  |  | 2013 |  |  | 2012 |
Minimum exercise price |  | $ | 6.21 |  |  | $ | 6.21 |  |  | $ | 6.21 |
Maximum exercise price |  |  | 35.88 |  |  |  | 40.28 |  |  |  | 40.28 |
Average remaining option term (Years) |  | 2.0 |  |  | 1.4 |  |  | 1.9 |
|  | 2014 |
Minimum exercise price |  | $ | 5.19 |
Maximum exercise price |  |  | 24.46 |
Average remaining option term (Years) |  | 3.1 |
Schedule of Share-based Compensation Arrangement by Share-based Payment Award Options Information Related to Stock Option Grants and Exercised [Table Text Block] |
|  | 2014 |  |  | 2013 |  |  | 2012 |
Aggregate intrinsic value of stock options exercised |  | $ | 11,000 |  |  | $ | 408,000 |  |  | $ | 307,000 |
Cash received from stock option exercises |  |  | 50,000 |  |  |  | 289,000 |  |  |  | 227,000 |
Tax benefit realized from stock option exercises |  |  | 0 |  |  |  | 0 |  |  |  | 0 |
Weighted average per share fair value of stock options granted |  | $ | 2.72 |  |  |  | NA |  |  |  | NA |
|  | 2014 |
Aggregate intrinsic value of stock options exercised |  | $ | 333,000 |
Cash received from stock option exercises |  |  | 232,000 |
Tax benefit realized from stock option exercises |  |  | 116,000 |
Weighted average per share fair value of stock options granted |  | NA |
Firstbank Plans [Member] |
Note 12 - Stock-based Compensation (Tables) [Line Items] |
Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block] |
|  | 2014 |
|  |  |  |  |  | Weighted |
|  |  |  |  |  | Average |
|  |  |  |  |  | Exercise |
|  | Shares |  |  | Price |
Outstanding at beginning of year |  |  | 0 |  |  |  | 0 |
Granted |  |  | 0 |  |  |  | 0 |
Replaced as part of merger |  |  | 282,178 |  |  |  | 15.48 |
Exercised |  |  | (27,740 | ) |  |  | 8.34 |
Forfeited or expired |  |  | (36,456 | ) |  |  | 24.46 |
Outstanding at end of year |  |  | 217,982 |  |  | $ | 14.89 |
Options exercisable at year-end |  |  | 210,777 |  |  | $ | 15.22 |

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- 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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Tabular disclosure of the number and weighted-average exercise prices (or conversion ratios) for share options (or share units) that were outstanding at the beginning and end of the year, vested and expected to vest, exercisable or convertible at the end of the year, and the number of share options or share units that were granted, exercised or converted, forfeited, and expired during the year. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Tabular disclosure of the significant assumptions used during the year to estimate the fair value of stock options, including, but not limited to: (a) expected term of share options and similar instruments, (b) expected volatility of the entity's shares, (c) expected dividends, (d) risk-free rate(s), and (e) discount for post-vesting restrictions. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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