REGULATORY CAPITAL AND OTHER REGULATORY MATTERS (Schedule of Regulatory Capital) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
First Banks, Inc.
Total capital (to risk-weighted assets):
Total capital	$ 405,856	$ 93,542
Total capital to risk-weighted assets, percentage	11.13%	2.57%
Total capital required for capital adequacy purposes, percentage	8.00%
Tier 1 capital (to risk-weighted assets):
Tier 1 capital	239,868	46,771
Tier 1 capital to risk-weighted assets, percentage	6.58%	1.28%
Tier 1 capital required for capital adequacy purposes, percentage	4.00%
Tier 1 capital (to average assets):
Tier 1 capital	239,868	46,771
Tier 1 capital to average assets, percentage	4.12%	0.73%
Tier 1 capital required for capital adequacy purposes, percentage	4.00%
First Bank
Total capital (to risk-weighted assets):
Total capital	734,535	626,177
Total capital to risk-weighted assets, percentage	20.12%	17.18%
Total capital required for capital adequacy purposes, percentage	8.00%
Total capital required to be well capitalized under prompt corrective action provisions, percentage	10.00%
Tier 1 capital (to risk-weighted assets):
Tier 1 capital	688,427	580,026
Tier 1 capital to risk-weighted assets, percentage	18.86%	15.92%
Tier 1 capital required for capital adequacy purposes, percentage	4.00%
Tier 1 capital required to be well capitalized under prompt corrective action provisions, percentage	6.00%
Tier 1 capital (to average assets):
Tier 1 capital	$ 688,427	$ 580,026
Tier 1 capital to average assets, percentage	11.77%	9.13%
Tier 1 capital required for capital adequacy purposes, percentage	4.00%
Tier 1 capital required to be well capitalized under prompt corrective action provisions, percentage	5.00%

The amount of total capital as defined in the regulations.

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The minimum Total risk based capital ratio (total capital divided by risk weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The Total risk based capital ratio (total capital divided by risk weighted assets) required to be categorized as "well capitalized", in the regulatory framework for prompt corrective action.

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Total Capital divided by risk weighted assets as defined in the regulations.

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Tier 1 Leverage Capital as defined in the regulations. Also called Core Capital.

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Tier 1 Risk Based Capital as defined in the regulations.

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The minimum Tier One Capital Ratio (Tier one capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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Tier 1 capital divided by risk weighted assets as defined by regulations.

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