Regulatory Matters (Details) $ in Thousands		6 Months Ended
		Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Regulatory Matters [Abstract]
Undivided profits		$ 86,600
Tier 1 capital to average assets [Abstract]
Capital conservation buffer		0.0250		0.0250
Components of regulatory capital [Abstract]
Total shareholders' equity		$ 395,974	$ 387,329	$ 389,522	$ 355,123	$ 335,618	$ 350,169
Add (deduct) [Abstract]
Accumulated other comprehensive income for regulatory purposes		8,416		10,024
Subordinated debt		$ 39,319		39,281
Period of transition method for regulatory purposes		3 years
Consolidated [Member]
Total capital to risk-weighted assets [Abstract]
Total risk-based capital	[1]	$ 474,100		$ 455,072
Actual, Ratio	[1]	0.1544		0.1595
Minimum for Adequately Capitalized Institutions, Amount	[1]	$ 245,683		$ 228,214
Minimum for Adequately Capitalized Institutions, Ratio	[1]	0.0800		0.0800
Tier 1 capital to risk-weighted assets [Abstract]
Actual, Amount	[1]	$ 395,701		$ 379,395
Actual, Ratio	[1]	0.1288		0.1330
Minimum for Adequately Capitalized Institutions, Amount	[1]	$ 184,263		$ 171,161
Minimum for Adequately Capitalized Institutions, Ratio	[1]	0.0600		0.0600
Common equity tier 1 capital to risk-weighted assets [Abstract]
Actual, Amount	[1]	$ 357,367		$ 341,095
Actual, Ratio	[1]	0.1164		0.1196
Minimum for Adequately Capitalized Institutions, Amount	[1]	$ 138,197		$ 128,370
Minimum for Adequately Capitalized Institutions, Ratio	[1]	0.0450		0.0450
Tier 1 capital to average assets [Abstract]
Tier 1 capital	[1]	$ 395,701		$ 379,395
Actual, Ratio	[1]	0.0900		0.0915
Minimum for Adequately Capitalized Institutions, Amount	[1]	$ 175,868		$ 165,825
Minimum for Adequately Capitalized Institutions, Ratio	[1]	0.0400		0.0400
Components of regulatory capital [Abstract]
Total shareholders' equity		$ 395,974		$ 389,522
Add (deduct) [Abstract]
Accumulated other comprehensive income for regulatory purposes		(14,213)		(15,821)
Goodwill and other intangibles		(32,121)		(32,606)
CECL	[2]	7,727		0
Common equity tier 1 capital	[1]	357,367		341,095
Qualifying trust preferred securities		38,334		38,300
Tier 1 capital	[1]	395,701		379,395
Subordinated debt		40,000		40,000
Allowance for credit losses and allowance for unfunded lending commitments limited to 1.25% of total risk-weighted assets	[3]	38,399		35,677
Total risk-based capital	[1]	474,100		455,072
Independent Bank [Member]
Total capital to risk-weighted assets [Abstract]
Total risk-based capital	[1]	$ 420,724		$ 401,005
Actual, Ratio	[1]	0.1371		0.1406
Minimum for Adequately Capitalized Institutions, Amount	[1]	$ 245,486		$ 228,111
Minimum for Adequately Capitalized Institutions, Ratio	[1]	0.0800		0.0800
Minimum for Well-Capitalized Institutions, Amount	[1]	$ 306,857		$ 285,139
Minimum for Well-Capitalized Institutions, Ratio	[1]	0.1000		0.1000
Tier 1 capital to risk-weighted assets [Abstract]
Actual, Amount	[1]	$ 382,355		$ 365,343
Actual, Ratio	[1]	0.1246		0.1281
Minimum for Adequately Capitalized Institutions, Amount	[1]	$ 184,114		$ 171,083
Minimum for Adequately Capitalized Institutions, Ratio	[1]	0.0600		0.0600
Minimum for Well-Capitalized Institutions, Amount	[1]	$ 245,486		$ 228,111
Minimum for Well-Capitalized Institutions, Ratio	[1]	0.0800		0.0800
Common equity tier 1 capital to risk-weighted assets [Abstract]
Actual, Amount	[1]	$ 382,355		$ 365,343
Actual, Ratio	[1]	0.1246		0.1281
Minimum for Adequately Capitalized Institutions, Amount	[1]	$ 138,086		$ 128,312
Minimum for Adequately Capitalized Institutions, Ratio	[1]	0.0450		0.0450
Minimum for Well-Capitalized Institutions, Amount	[1]	$ 199,457		$ 185,340
Minimum for Well-Capitalized Institutions, Ratio	[1]	0.0650		0.0650
Tier 1 capital to average assets [Abstract]
Tier 1 capital	[1]	$ 382,355		$ 365,343
Actual, Ratio	[1]	0.0869		0.0881
Minimum for Adequately Capitalized Institutions, Amount	[1]	$ 175,936		$ 165,828
Minimum for Adequately Capitalized Institutions, Ratio	[1]	0.0400		0.0400
Minimum for Well-Capitalized Institutions, Amount	[1]	$ 219,921		$ 207,285
Minimum for Well-Capitalized Institutions, Ratio	[1]	0.0500		0.0500
Components of regulatory capital [Abstract]
Total shareholders' equity		$ 420,962		$ 413,770
Add (deduct) [Abstract]
Accumulated other comprehensive income for regulatory purposes		(14,213)		(15,821)
Goodwill and other intangibles		(32,121)		(32,606)
CECL	[2]	7,727		0
Common equity tier 1 capital	[1]	382,355		365,343
Qualifying trust preferred securities		0		0
Tier 1 capital	[1]	382,355		365,343
Subordinated debt		0		0
Allowance for credit losses and allowance for unfunded lending commitments limited to 1.25% of total risk-weighted assets	[3]	38,369		35,662
Total risk-based capital	[1]	$ 420,724		$ 401,005

[1] These ratios do not reflect a capital conservation buffer of 2.50% at June 30, 2021 and December 31, 2020.

[2] We elected the three year CECL transition method for regulatory purposes.

[3] Beginning January 1, 2021, calculation of allowances are based on CECL methodology. Prior to January 1, 2021, calculation was based on the probable incurred loss methodology.