REGULATORY CAPITAL AND OTHER REGULATORY MATTERS (Schedule of Regulatory Capital ) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
First Banks, Inc. [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital	$ 458,806		$ 405,856
Total Capital to Risk-Weighted Assets	12.39%		11.13%
Total Capital Required for Capital Adequacy	8.00%
Tier One Capital	274,767		239,868
Tier One Capital to Risk-Weighted Assets	7.42%		6.58%
Tier One Capital Required for Capital Adequacy	4.00%
Tier One Leverage Capital	274,767		239,868
Tier One Leverage Capital to Average Assets	4.86%		4.12%
Tier One Leverage Capital Required for Capital Adequacy	4.00%
First Bank [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital	687,643	[1]	734,535
Total Capital to Risk-Weighted Assets	18.56%	[1]	20.12%
Total Capital Required for Capital Adequacy	8.00%
Total Capital Required to be Well Capitalized	10.00%
Tier One Capital	640,940	[1]	688,427
Tier One Capital to Risk-Weighted Assets	17.30%	[1]	18.86%
Tier One Capital Required for Capital Adequacy	4.00%
Tier One Capital Required to be Well Capitalized	6.00%
Tier One Leverage Capital	$ 640,940	[1]	$ 688,427
Tier One Leverage Capital to Average Assets	11.37%	[1]	11.77%
Tier One Leverage Capital Required for Capital Adequacy	4.00%
Tier One Leverage Capital Required to be Well Capitalized	5.00%

[1] The reduction in First Bank's regulatory capital ratios during the first nine months of 2014 primarily resulted from the payment of a $70 million dividend to the Company in February 2014, as further described below.