Regulatory Matters (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Regulatory Matters [Abstract]
Undivided profits	$ 26,900
Components of regulatory capital [Abstract]
Total shareholders' equity	337,083	$ 264,933	$ 262,453	$ 248,980
Add (deduct) [Abstract]
Accumulated other comprehensive loss for regulatory purposes	(9,214)	(5,999)
Intangible assets	(7,004)	(1,586)
Consolidated [Member]
Total capital to risk-weighted assets [Abstract]
Total risk-based capital	$ 359,585	$ 312,163
Actual, Ratio	14.49%	15.16%
Minimum for Adequately Capitalized Institutions, Amount	$ 198,495	$ 164,782
Minimum for Adequately Capitalized Institutions, Ratio	8.00%	8.00%
Tier 1 capital to risk-weighted assets [Abstract]
Actual, Amount	$ 335,033	$ 288,451
Actual, Ratio	13.50%	14.00%
Minimum for Adequately Capitalized Institutions, Amount	$ 148,871	$ 123,586
Minimum for Adequately Capitalized Institutions, Ratio	6.00%	6.00%
Common equity tier 1 capital to risk-weighted assets [Abstract]
Actual, Amount	$ 296,903	$ 255,934
Actual, Ratio	11.97%	12.43%
Minimum for Adequately Capitalized Institutions, Amount	$ 111,654	$ 92,690
Minimum for Adequately Capitalized Institutions, Ratio	4.50%	4.50%
Tier 1 capital to average assets [Abstract]
Tier 1 capital	$ 335,033	$ 288,451
Actual, Ratio	10.70%	10.57%
Minimum for Adequately Capitalized Institutions, Amount	$ 125,215	$ 109,209
Minimum for Adequately Capitalized Institutions, Ratio	4.00%	4.00%
Components of regulatory capital [Abstract]
Total shareholders' equity	$ 337,083	$ 264,933
Add (deduct) [Abstract]
Accumulated other comprehensive loss for regulatory purposes	3,417	201
Intangible assets	(36,016)	(1,269)
Disallowed deferred tax assets	(7,581)	(7,931)
Common equity tier 1 capital	296,903	255,934
Qualifying trust preferred securities	38,130	34,500
Disallowed deferred tax assets	0	(1,983)
Tier 1 capital	335,033	288,451
Allowance for loan losses and allowance for unfunded lending commitments limited to 1.25% of total risk-weighted assets	24,552	23,712
Total risk-based capital	359,585	312,163
Independent Bank [Member]
Total capital to risk-weighted assets [Abstract]
Total risk-based capital	$ 335,404	$ 290,188
Actual, Ratio	13.52%	14.10%
Minimum for Adequately Capitalized Institutions, Amount	$ 198,431	$ 164,675
Minimum for Adequately Capitalized Institutions, Ratio	8.00%	8.00%
Minimum for Well Capitalized Institutions, Amount	$ 248,038	$ 205,843
Minimum for Well-Capitalized Institutions, Ratio	10.00%	10.00%
Tier 1 capital to risk-weighted assets [Abstract]
Actual, Amount	$ 310,852	$ 266,476
Actual, Ratio	12.53%	12.95%
Minimum for Adequately Capitalized Institutions, Amount	$ 148,823	$ 123,506
Minimum for Adequately Capitalized Institutions, Ratio	6.00%	6.00%
Minimum for Well-Capitalized Institutions, Amount	$ 198,431	$ 164,675
Minimum for Well Capitalized Institutions, Ratio	8.00%	8.00%
Common equity tier 1 capital to risk-weighted assets [Abstract]
Actual, Amount	$ 310,852	$ 266,476
Actual, Ratio	12.53%	12.95%
Minimum for Adequately Capitalized Institutions, Amount	$ 111,617	$ 92,630
Minimum for Adequately Capitalized Institutions, Ratio	4.50%	4.50%
Minimum for Well-Capitalized Institutions, Amount	$ 161,225	$ 133,798
Minimum for Well Capitalized Institutions, Ratio	6.50%	6.50%
Tier 1 capital to average assets [Abstract]
Tier 1 capital	$ 310,852	$ 266,476
Actual, Ratio	9.93%	9.78%
Minimum for Adequately Capitalized Institutions, Amount	$ 125,156	$ 109,041
Minimum for Adequately Capitalized Institutions, Ratio	4.00%	4.00%
Minimum for Well-Capitalized Institutions, Amount	$ 156,445	$ 136,301
Minimum for Well-Capitalized Institutions, Ratio	5.00%	5.00%
Components of regulatory capital [Abstract]
Total shareholders' equity	$ 343,500	$ 269,481
Add (deduct) [Abstract]
Accumulated other comprehensive loss for regulatory purposes	3,417	201
Intangible assets	(36,016)	(1,269)
Disallowed deferred tax assets	(49)	(1,937)
Common equity tier 1 capital	310,852	266,476
Qualifying trust preferred securities	0	0
Disallowed deferred tax assets	0	0
Tier 1 capital	310,852	266,476
Allowance for loan losses and allowance for unfunded lending commitments limited to 1.25% of total risk-weighted assets	24,552	23,712
Total risk-based capital	$ 335,404	$ 290,188