Note 25 - Firstbank Corporation (Parent Company Only) Condensed Financial Information (Details) - Condensed Statements of Income and Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Income Statements, Captions [Line Items]
Dividends and returns of capital from subsidiaries (net of capital infusions)	$ 15,308	$ 8,150	$ 3,680
Net Interest Expense	52,100	54,492	54,672
Income before income tax and undistributed subsidiary income	11,597	3,928	1,161
Income tax benefit	5,134	4,256	1,834
Net income	12,234	10,534	5,623
Comprehensive income	8,873	11,246	8,373
Parent Company [Member]
Condensed Income Statements, Captions [Line Items]
Net Interest Expense	(678)	(992)	(1,110)
Other income	211	6,813	7,031
Other expense	(3,244)	(10,043)	(8,440)
Income tax benefit	1,152	1,416	844
Equity in undistributed subsidiary income/(loss)	(515)	5,190	3,618
Net income	12,234	10,534	5,623
Change in unrealized gain (loss) on securities, net of tax and classification effects	(3,361)	712	2,750
Subsidiary of Common Parent [Member]
Condensed Income Statements, Captions [Line Items]
Equity in undistributed subsidiary income/(loss)	$ (515)	$ 5,190	$ 3,618