EARNINGS (LOSS) PER COMMON SHARE (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Class of Stock [Line Items]
Net income from continuing operations attributable to First Banks, Inc.	$ 6,741	$ 10,655	$ 28,312	$ 29,642
Preferred stock dividends declared and undeclared	(5,013)	(4,753)	(14,841)	(14,070)
Accretion of discount on preferred stock	(919)	(893)	(2,725)	(2,660)
Net income from continuing operations attributable to common stockholders	809	5,009	10,746	12,912
Net loss from discontinued operations attributable to common stockholders	(881)	(2,182)	(6,279)	(6,763)
Net (loss) income available to common stockholders	(72)	2,827	4,467	6,149
Weighted average shares of common stock outstanding (in shares)	23,661	23,661	23,661	23,661
Basic earnings per common share - continuing operations (in dollars per share)	$ 34.19	$ 211.70	$ 454.17	$ 545.72
Basic loss per common share - discontinued operations (in dollars per share)	$ (37.23)	$ (92.22)	$ (265.37)	$ (285.83)
Basic (loss) earnings per common share (in dollars per share)	$ (3.04)	$ 119.48	$ 188.80	$ 259.89
Net income from continuing operations attributable to common stockholders	809	5,009	10,746	12,912
Net loss from discontinued operations attributable to common stockholders	(881)	(2,182)	(6,279)	(6,763)
Diluted (loss) income available to First Banks, Inc. common stockholders	(72)	2,827	4,467	6,149
Weighted average diluted shares of common stock outstanding (in shares)	23,661	23,661	23,661	23,661
Diluted earnings per common share - continuing operations (in dollars per share)	$ 34.19	$ 211.70	$ 454.17	$ 545.72
Diluted loss per common share - discontinued operations (in dollars per share)	$ (37.23)	$ (92.22)	$ (265.37)	$ (285.83)
Diluted (loss) earnings per common share	$ (3.04)	$ 119.48	$ 188.80	$ 259.89
Class A Convertible Adjustable Rate Preferred Stock [Member]
Class of Stock [Line Items]
Effect of dilutive securities – Class A convertible preferred stock	$ 0	$ 0	$ 0	$ 0
Effect of dilutive securities – Class A convertible preferred stock	0	0	0	0