PARENT COMPANY ONLY FINANCIAL INFORMATION (CONDENSED STATEMENTS OF OPERATIONS) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income:
Loss on available-for-sale investment securities	$ (374)	$ (1)	$ (31)
Expense:
Interest	30,088	44,539	76,020
Income (loss) from continuing operations before provision (benefit) for income taxes	31,365	(48,295)	(197,699)
Benefit for income taxes	(139)	(10,654)	4,114
Net income (loss) attributable to First Banks, Inc.	26,278	(41,150)	(191,737)
Parent Company
Income:
Management fees from subsidiaries	3	28	193
Net loss on derivative instruments	(43)	(194)	(2,929)
Other	578	509	3,123
Total income	538	343	387
Expense:
Interest	14,847	13,623	13,012
Other	1,506	(374)	809
Total expense	16,353	13,249	13,821
Income (loss) from continuing operations before provision (benefit) for income taxes	(15,815)	(12,906)	(13,434)
Benefit for income taxes	(348)	(46)	(171)
Loss before equity in undistributed earnings (losses) of subsidiaries	(15,467)	(12,860)	(13,263)
Equity in undistributed earnings (losses) of subsidiaries	41,745	(28,290)	(178,474)
Net income (loss) attributable to First Banks, Inc.	$ 26,278	$ (41,150)	$ (191,737)