Regulatory Matters (Details) (USD $)					9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2012 Consolidated [Member]	Dec. 31, 2011 Consolidated [Member]	Sep. 30, 2012 Independent Bank [Member]	Dec. 31, 2011 Independent Bank [Member]	Sep. 30, 2012 Board Established Ratios [Member]	Sep. 30, 2012 Minimum Ratio To Be Well Capitalized [Member]
Regulatory Matters [Abstract]
Past due assets disposition plan amount to be reported	$ 1,000,000
Total capital to risk-weighted assets [Abstract]
Actual Amount					189,627,000	174,547,000	192,779,000	175,868,000
Minimum for Adequately Capitalized Institutions, Amount					116,898,000	123,470,000	116,682,000	123,254,000
Minimum for Well Capitalized Institutions, Amount					0	0	145,853,000	154,068,000
Actual Ratio (in hundredths)					12.98%	11.31%	13.22%	11.41%	11.00%	10.00%
Minimum for Adequately Capitalized Institutions Ratio (in hundredths)					8.00%	8.00%	8.00%	8.00%
Minimum for Well-Capitalized Institutions (in hundredths)					0.00%	0.00%	10.00%	10.00%
Tier 1 capital to risk-weighted assets [Abstract]
Actual Amount					165,638,000	144,265,000	174,171,000	156,104,000
Minimum for Adequately Capitalized Institutions, Amount					58,449,000	61,735,000	58,341,000	61,627,000
Minimum for Well-Capitalized Institutions, Amount					0	0	87,512,000	92,441,000
Actual Ratio (in hundredths)					11.34%	9.35%	11.94%	10.13%
Minimum for Adequately Capitalized Institutions, Ratio (in hundredths)					4.00%	4.00%	4.00%	4.00%
Minimum for Well Capitalized Institutions, Ratio (in hundredths)					0.00%	0.00%	6.00%	6.00%
Tier 1 capital to average assets [Abstract]
Actual Amount					165,638,000	144,265,000	174,171,000	156,104,000
Minimum for Adequately Capitalized Institutions, Amount					95,732,000	92,338,000	95,626,000	92,268,000
Minimum for Well-Capitalized Institutions, Amount					0	0	119,533,000	115,335,000
Actual Ratio (in hundredths)					6.92%	6.25%	7.29%	6.77%	8.00%	5.00%
Minimum for Adequately Capitalized Institutions, Ratio (in hundredths)	8.00%				4.00%	4.00%	4.00%	4.00%
Minimum for Well-Capitalized Institutions, Ratio (in hundredths)					0.00%	0.00%	5.00%	5.00%
Components of regulatory capital [Abstract]
Total shareholders' equity	121,528,000	102,627,000	110,802,000	119,085,000	121,528,000	102,627,000	173,283,000	152,987,000
Add (deduct) [Abstract]
Qualifying trust preferred securities					43,320,000	38,183,000	0	0
Accumulated other comprehensive loss	(8,432,000)	(11,921,000)			8,432,000	11,921,000	8,530,000	11,583,000
Intangible assets	(6,793,000)	(7,609,000)			(6,793,000)	(7,609,000)	(6,793,000)	(7,609,000)
Disallowed capitalized mortgage loan servicing rights					(849,000)	(857,000)	(849,000)	(857,000)
Tier 1 capital					165,638,000	144,265,000	174,171,000	156,104,000
Qualifying trust preferred securities II					5,348,000	10,485,000	0	0
Allowance for loan losses and allowance for unfunded lending commitments					18,641,000	19,797,000	18,608,000	19,764,000
Total risk-based capital					$ 189,627,000	$ 174,547,000	$ 192,779,000	$ 175,868,000
Actual, minimum board imposed and ratios necessary to be well capitalized [Abstract]
Total Capital to Risk-Weighted Assets (in hundredths)					12.98%	11.31%	13.22%	11.41%	11.00%	10.00%
Tier 1 Capital to Average Total Assets (in hundredths)					6.92%	6.25%	7.29%	6.77%	8.00%	5.00%