EARNINGS (LOSS) PER COMMON SHARE (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share [Abstract]
Net income from continuing operations attributable to First Banks, Inc.	$ 6,042	$ 6,741	$ 16,678	$ 28,312
Preferred stock dividends declared	0	(5,013)	0	(14,841)
Accretion of discount on preferred stock	0	(919)	0	(2,725)
Net income from continuing operations attributable to common stockholders	6,042	809	16,678	10,746
Loss from discontinued operations, net of tax	0	(881)	0	(6,279)
Net income (loss) available to common stockholders	6,042	(72)	16,678	4,467
Effect of dilutive Securities - Class A convertible preferred stock	0	0	0	0
Diluted income (loss) available to First Banks, Inc. common stockholders	$ 6,042	$ (72)	$ 16,678	$ 4,467
Weighted average shares of common stock outstanding (in shares)	23,661	23,661	23,661	23,661
Effect of dilutive securities – Class A convertible preferred stock (in shares)	3,501	0	3,942	0
Weighted average diluted shares of common stock outstanding (in shares)	27,162	23,661	27,603	23,661
Basic earnings per common share - continuing operations (in dollars per share)	$ 255.34	$ 34.19	$ 704.88	$ 454.17
Basic loss per common share - discontinued operations (in dollars per share)	$ 0.00	$ (37.23)	$ 0.00	$ (265.37)
Basic earnings (loss) per common share (in dollars per share)	$ 255.34	$ (3.04)	$ 704.88	$ 188.80
Diluted earnings per common share - continuing operations (in dollars per share)	$ 222.43	$ 34.19	$ 604.22	$ 454.17
Diluted loss per common share - discontinued operations (in dollars per share)	$ 0.00	$ (37.23)	$ 0.00	$ (265.37)
Diluted earnings (loss) per common share (in dollars per share)	$ 222.43	$ (3.04)	$ 604.22	$ 188.80