Regulatory Matters (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2024 USD ($)	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Jun. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Banking Regulation, Tier 1 Leverage Capital [Abstract]
Capital conservation buffer	0.0250		0.0250
Components of regulatory capital [Abstract]
Total shareholders' equity	$ 430,459	$ 415,570	$ 404,449	$ 375,162	$ 367,714	$ 347,596
Add (deduct)
Accumulated other comprehensive (income) loss for regulatory purposes	(70,828)		(72,142)
Subordinated debt	$ 39,548		39,510
Period of transition method for regulatory purposes	3 years
Consolidated
Banking Regulation, Total Capital [Abstract]
Total risk-based capital	$ 596,563		$ 573,972
Actual, ratio	0.1421		0.1371
Banking regulation, total risk-based capital, capital adequacy, minimum	$ 335,844		$ 335,014
Minimum for adequately capitalized institutions, ratio	0.0800		0.0800
Tier 1 capital to risk-weighted assets [Abstract]
Actual, amount	$ 503,981		$ 481,569
Banking regulation, tier 1 risk-based capital ratio, accrual	0.1201		0.1150
Minimum for adequately capitalized institutions, amount	$ 251,883		$ 251,260
Minimum for adequately capitalized institutions, ratio	0.0600		0.0600
Common equity tier 1 capital to risk-weighted assets [Abstract]
Actual, amount	$ 465,443		$ 443,065
Actual, ratio	0.1109		0.1058
Minimum for adequately capitalized institutions, amount	$ 188,912		$ 188,445
Minimum for adequately capitalized institutions, ratio	0.0450		0.0450
Banking Regulation, Tier 1 Leverage Capital [Abstract]
Tier 1 capital	$ 503,981		$ 481,569
Actual, ratio	0.0959		0.0903
Minimum for adequately capitalized institutions, amount	$ 210,192		$ 213,227
Minimum for adequately capitalized institutions, ratio	0.0400		0.0400
Components of regulatory capital [Abstract]
Total shareholders' equity	$ 430,459		$ 404,449
Add (deduct)
Accumulated other comprehensive (income) loss for regulatory purposes	65,030		66,344
Goodwill and other intangibles	(30,046)		(30,304)
CECL	0		2,576
Common equity tier 1 capital	465,443		443,065
Qualifying trust preferred securities	38,538		38,504
Tier 1 capital	503,981		481,569
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	52,582		52,403
Total risk-based capital	596,563		573,972
Independent Bank
Banking Regulation, Total Capital [Abstract]
Total risk-based capital	$ 543,231		$ 521,374
Actual, ratio	0.1295		0.1246
Banking regulation, total risk-based capital, capital adequacy, minimum	$ 335,487		$ 334,673
Minimum for adequately capitalized institutions, ratio	0.0800		0.0800
Minimum for well-capitalized institutions, amount	$ 419,359		$ 418,341
Minimum for well-capitalized institutions, ratio	0.1000		0.1000
Tier 1 capital to risk-weighted assets [Abstract]
Actual, amount	$ 490,704		$ 469,023
Banking regulation, tier 1 risk-based capital ratio, accrual	0.1170		0.1121
Minimum for adequately capitalized institutions, amount	$ 251,615		$ 251,005
Minimum for adequately capitalized institutions, ratio	0.0600		0.0600
Minimum for well-capitalized institutions, amount	$ 335,487		$ 334,673
Minimum for well capitalized institutions, ratio	0.0800		0.0800
Common equity tier 1 capital to risk-weighted assets [Abstract]
Actual, amount	$ 490,704		$ 469,023
Actual, ratio	0.1170		0.1121
Minimum for adequately capitalized institutions, amount	$ 188,712		$ 188,254
Minimum for adequately capitalized institutions, ratio	0.0450		0.0450
Minimum for well-capitalized institutions, amount	$ 272,583		$ 271,922
Minimum for well-capitalized institutions, ratio	0.0650		0.0650
Banking Regulation, Tier 1 Leverage Capital [Abstract]
Tier 1 capital	$ 490,704		$ 469,023
Actual, ratio	0.0934		0.0880
Minimum for adequately capitalized institutions, amount	$ 210,197		$ 213,180
Minimum for adequately capitalized institutions, ratio	0.0400		0.0400
Banking regulation, tier 1 leverage, capital, well capitalized, minimum	$ 262,747		$ 266,475
Minimum for well capitalized institutions, ratio	0.0500		0.0500
Components of regulatory capital [Abstract]
Total shareholders' equity	$ 455,720		$ 430,407
Add (deduct)
Accumulated other comprehensive (income) loss for regulatory purposes	65,030		66,344
Goodwill and other intangibles	(30,046)		(30,304)
CECL	0		2,576
Common equity tier 1 capital	490,704		469,023
Qualifying trust preferred securities	0		0
Tier 1 capital	490,704		469,023
Subordinated debt	0		0
Allowance for credit losses and allowance for unfunded lending commitments limited to 1.25% of total risk-weighted assets	52,527		52,351
Total risk-based capital	$ 543,231		$ 521,374