Capital (Details 2) (USD $)	0 Months Ended
	Jan. 22, 2013	Dec. 31, 2012	Dec. 31, 2011
Total Capital (to Risk Weighted Assets), Amount
Actual		$ 419,343,000	$ 407,801,000
Minimum Capital Requirement		180,026,000	174,946,000
Minimum To Be Well Capitalized		225,033,000	218,682,000
Total Capital (to Risk Weighted Assets), Ratio
Actual (as a percent)		18.63%	18.65%
Minimum Capital Requirement (as a percent)		8.00%	8.00%
Minimum To Be Well Capitalized (as a percent)		10.00%	10.00%
Tier I Capital (to Risk Weighted Assets), Amount
Actual		390,304,000	379,483,000
Minimum Capital Requirement		90,013,000	87,473,000
Minimum To Be Well Capitalized		135,020,000	131,210,000
Tier I Capital (to Risk Weighted Assets), Ratio
Actual (as a percent)		17.34%	17.35%
Minimum Capital Requirement (as a percent)		4.00%	4.00%
Minimum To Be Well Capitalized (as a percent)		6.00%	6.00%
Tier I Capital (to Average Assets), Amount
Actual		390,304,000	379,483,000
Minimum Capital Requirement		138,151,000	132,022,000
Tier I Capital (to Average Assets), Ratio
Actual (as a percent)		11.30%	11.50%
Minimum Capital Requirement (as a percent)		4.00%	4.00%
Maximum assets of bank holding companies for inclusion of proceeds of trust preferred securities from Tier 1 capital unless such securities were issued prior to May 19, 2010		15,000,000,000
Busey Bank
Regulatory Capital
Distribution received through chartered amendment	50,000,000
Total Capital (to Risk Weighted Assets), Amount
Actual		406,597,000	375,154,000
Minimum Capital Requirement		179,278,000	173,815,000
Minimum To Be Well Capitalized		224,097,000	217,268,000
Total Capital (to Risk Weighted Assets), Ratio
Actual (as a percent)		18.14%	17.27%
Minimum Capital Requirement (as a percent)		8.00%	8.00%
Minimum To Be Well Capitalized (as a percent)		10.00%	10.00%
Tier I Capital (to Risk Weighted Assets), Amount
Actual		377,673,000	347,011,000
Minimum Capital Requirement		89,639,000	86,908,000
Minimum To Be Well Capitalized		134,458,000	130,361,000
Tier I Capital (to Risk Weighted Assets), Ratio
Actual (as a percent)		16.85%	15.97%
Minimum Capital Requirement (as a percent)		4.00%	4.00%
Minimum To Be Well Capitalized (as a percent)		6.00%	6.00%
Tier I Capital (to Average Assets), Amount
Actual		377,673,000	347,011,000
Minimum Capital Requirement		137,488,000	130,924,000
Minimum To Be Well Capitalized		$ 171,859,000	$ 163,654,000
Tier I Capital (to Average Assets), Ratio
Actual (as a percent)		10.99%	10.60%
Minimum Capital Requirement (as a percent)		4.00%	4.00%
Minimum To Be Well Capitalized (as a percent)		5.00%	5.00%