Regulatory Matters (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) election	Dec. 31, 2016 USD ($)
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Available election to opt out, accepted | election	1
Centrue Financial
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total capital (to risk-weighted assets), actual amount	$ 118,359	$ 118,841
Total capital (to risk-weighted assets), actual ratio	15.60%	15.00%
Common equity tier I (to risk-weighted assets), actual amount	$ 107,678	$ 109,434
Common equity tier I (to risk-weighted assets), actual ratio	14.20%	13.80%
Tier I capital (to risk-weighted assets), actual amount	$ 109,768	$ 109,937
Tier I capital (to risk-weighted assets), actual ratio	14.50%	13.80%
Tier I leverage ratio (to average assets), actual amount	$ 109,768	$ 109,937
Tier I leverage ratio (to average assets), actual ratio	12.10%	11.50%
Centrue Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total capital (to risk-weighted assets), actual amount	$ 117,807	$ 115,455
Total capital (to risk-weighted assets), actual ratio	15.60%	14.50%
Total capital (to risk-weighted assets), to be adequately capitalized, amount	$ 60,463	$ 63,556
Total capital (to risk-weighted assets), to be adequately capitalized, ratio	8.00%	8.00%
Total capital (to risk-weighted assets), to be well capitalized under prompt corrective action provisions, amount	$ 75,579	$ 79,445
Total capital (to risk-weighted assets), to be well capitalized under prompt corrective action provisions, ratio	10.00%	10.00%
Common equity tier I (to risk-weighted assets), actual amount	$ 109,216	$ 106,551
Common equity tier I (to risk-weighted assets), actual ratio	14.50%	13.40%
Common equity tier I (to risk-weighted assets), to be adequately capitalized, amount	$ 34,011	$ 35,750
Common equity tier I (to risk-weighted assets), to be adequately capitalized, ratio	4.50%	4.50%
Common equity tier I (to risk-weighted assets), to be well capitalized under prompt corrective action provisions, amount	$ 49,126	$ 51,639
Common equity tier I (to risk-weighted assets), to be well capitalized under prompt corrective action provisions, ratio	6.50%	6.50%
Tier I capital (to risk-weighted assets), actual amount	$ 109,216	$ 106,551
Tier I capital (to risk-weighted assets), actual ratio	14.50%	13.40%
Tier I capital (to risk-weighted assets), to be adequately capitalized, amount	$ 45,347	$ 47,667
Tier I capital (to risk-weighted assets), to be adequately capitalized, ratio	6.00%	6.00%
Tier I capital (to risk-weighted assets), to be well capitalized under prompt corrective action provisions, amount	$ 60,463	$ 63,556
Tier I capital (to risk-weighted assets), to be well capitalized under prompt corrective action provisions, ratio	8.00%	8.00%
Tier I leverage ratio (to average assets), actual amount	$ 109,216	$ 106,551
Tier I leverage ratio (to average assets), actual ratio	12.00%	11.10%
Tier I leverage ratio (to average assets), to be adequately capitalized, amount	$ 36,505	$ 38,251
Tier I leverage ratio (to average assets), to be adequately capitalized, ratio	4.00%	4.00%
Tier I leverage ratio (to average assets), to be well capitalized under prompt corrective action provisions, amount	$ 45,631	$ 47,814
Tier I leverage ratio (to average assets), to be well capitalized under prompt corrective action provisions, ratio	5.00%	5.00%