REGULATORY CAPITAL AND OTHER REGULATORY MATTERS (Schedule of Regulatory Capital ) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
First Banks, Inc. [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital	$ 425,829		$ 405,856
Total Capital to Risk-Weighted Assets	11.73%		11.13%
Total Capital Required for Capital Adequacy	8.00%
Tier One Capital	253,332		239,868
Tier One Capital to Risk-Weighted Assets	6.98%		6.58%
Tier One Capital Required for Capital Adequacy	4.00%
Tier One Leverage Capital	253,332		239,868
Tier One Leverage Capital to Average Assets	4.51%		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	679,594	[1]	734,535
Total Capital to Risk-Weighted Assets	18.70%	[1]	20.12%
Total Capital Required for Capital Adequacy	8.00%
Total Capital Required to be Well Capitalized	10.00%
Tier One Capital	633,700	[1]	688,427
Tier One Capital to Risk-Weighted Assets	17.43%	[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	$ 633,700	[1]	$ 688,427
Tier One Leverage Capital to Average Assets	11.30%	[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 quarter of 2014 primarily resulted from the payment of a $70 million dividend to the Company, as further described below.