Regulatory Matters (Details) $ in Thousands		Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Regulatory Matters [Abstract]
Undivided profits		$ 48,400
Tier 1 capital to average assets [Abstract]
Capital conservation buffer		0.0250		0.0250
Components of regulatory capital [Abstract]
Total shareholders' equity		$ 355,123	$ 335,618	$ 350,169	$ 330,846	$ 344,726	$ 338,994
Add (deduct) [Abstract]
Accumulated other comprehensive income for regulatory purposes		3,796		(3,786)
Subordinated debt		39,283		0
Consolidated [Member]
Total capital to risk-weighted assets [Abstract]
Total risk-based capital	[1]	$ 425,443		$ 380,454
Actual, Ratio	[1]	0.1531		0.1374
Minimum for Adequately Capitalized Institutions, Amount	[1]	$ 222,368		$ 221,562
Minimum for Adequately Capitalized Institutions, Ratio	[1]	0.0800		0.0800
Tier 1 capital to risk-weighted assets [Abstract]
Actual, Amount	[1]	$ 350,680		$ 352,764
Actual, Ratio	[1]	0.1262		0.1274
Minimum for Adequately Capitalized Institutions, Amount	[1]	$ 166,776		$ 166,171
Minimum for Adequately Capitalized Institutions, Ratio	[1]	0.0600		0.0600
Common equity tier 1 capital to risk-weighted assets [Abstract]
Actual, Amount	[1]	$ 312,414		$ 314,532
Actual, Ratio	[1]	0.1124		0.1136
Minimum for Adequately Capitalized Institutions, Amount	[1]	$ 125,082		$ 124,628
Minimum for Adequately Capitalized Institutions, Ratio	[1]	0.0450		0.0450
Tier 1 capital to average assets [Abstract]
Tier 1 capital	[1]	$ 350,680		$ 352,764
Actual, Ratio	[1]	0.0915		0.1011
Minimum for Adequately Capitalized Institutions, Amount	[1]	$ 153,244		$ 139,632
Minimum for Adequately Capitalized Institutions, Ratio	[1]	0.0400		0.0400
Components of regulatory capital [Abstract]
Total shareholders' equity		$ 355,123		$ 350,169
Add (deduct) [Abstract]
Accumulated other comprehensive income for regulatory purposes		(9,593)		(2,011)
Goodwill and other intangibles		(33,116)		(33,626)
Common equity tier 1 capital	[1]	312,414		314,532
Qualifying trust preferred securities		38,266		38,232
Tier 1 capital	[1]	350,680		352,764
Subordinated debt		40,000		0
Allowance for loan losses and allowance for unfunded lending commitments limited to 1.25% of total risk-weighted assets		34,763		27,690
Total risk-based capital	[1]	425,443		380,454
Independent Bank [Member]
Total capital to risk-weighted assets [Abstract]
Total risk-based capital	[1]	$ 370,222		$ 358,914
Actual, Ratio	[1]	0.1332		0.1296
Minimum for Adequately Capitalized Institutions, Amount	[1]	$ 222,275		$ 221,482
Minimum for Adequately Capitalized Institutions, Ratio	[1]	0.0800		0.0800
Minimum for Well-Capitalized Institutions, Amount	[1]	$ 277,843		$ 276,852
Minimum for Well-Capitalized Institutions, Ratio	[1]	0.1000		0.1000
Tier 1 capital to risk-weighted assets [Abstract]
Actual, Amount	[1]	$ 335,473		$ 331,224
Actual, Ratio	[1]	0.1207		0.1196
Minimum for Adequately Capitalized Institutions, Amount	[1]	$ 166,706		$ 166,111
Minimum for Adequately Capitalized Institutions, Ratio	[1]	0.0600		0.0600
Minimum for Well-Capitalized Institutions, Amount	[1]	$ 222,275		$ 221,482
Minimum for Well-Capitalized Institutions, Ratio	[1]	0.0800		0.0800
Common equity tier 1 capital to risk-weighted assets [Abstract]
Actual, Amount	[1]	$ 335,473		$ 331,224
Actual, Ratio	[1]	0.1207		0.1196
Minimum for Adequately Capitalized Institutions, Amount	[1]	$ 125,029		$ 124,583
Minimum for Adequately Capitalized Institutions, Ratio	[1]	0.0450		0.0450
Minimum for Well-Capitalized Institutions, Amount	[1]	$ 180,598		$ 179,954
Minimum for Well-Capitalized Institutions, Ratio	[1]	0.0650		0.0650
Tier 1 capital to average assets [Abstract]
Tier 1 capital	[1]	$ 335,473		$ 331,224
Actual, Ratio	[1]	0.0876		0.0949
Minimum for Adequately Capitalized Institutions, Amount	[1]	$ 153,255		$ 139,615
Minimum for Adequately Capitalized Institutions, Ratio	[1]	0.0400		0.0400
Minimum for Well-Capitalized Institutions, Amount	[1]	$ 191,569		$ 174,519
Minimum for Well-Capitalized Institutions, Ratio	[1]	0.0500		0.0500
Components of regulatory capital [Abstract]
Total shareholders' equity		$ 378,182		$ 366,861
Add (deduct) [Abstract]
Accumulated other comprehensive income for regulatory purposes		(9,593)		(2,011)
Goodwill and other intangibles		(33,116)		(33,626)
Common equity tier 1 capital	[1]	335,473		331,224
Qualifying trust preferred securities		0		0
Tier 1 capital	[1]	335,473		331,224
Subordinated debt		0		0
Allowance for loan losses and allowance for unfunded lending commitments limited to 1.25% of total risk-weighted assets		34,749		27,690
Total risk-based capital	[1]	$ 370,222		$ 358,914

[1] These ratios do not reflect a capital conservation buffer of 2.50% at June 30, 2020 and December 31, 2019.