CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Thousands	Total	First Banks, Inc. Stockholders’ Equity, Preferred Stock [Member]	First Banks, Inc. Stockholders’ Equity, Common Stock [Member]	First Banks, Inc. Stockholders’ Equity, Additional Paid-In Capital [Member]	First Banks, Inc. Stockholders’ Equity, Retained Earnings [Member]	First Banks, Inc. Stockholders’ Equity, Accumulated Other Comprehensive Income [Member]	Noncontrolling Interest [Member]
Balance, beginning of period at Dec. 31, 2013	$ 488,256	$ 13,373	$ 5,915	$ 324,913	$ 42,719	$ 7,502	$ 93,834
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	16,592				16,678		(86)
Other comprehensive income (loss)	3,845					3,845
Balance, end of period at Sep. 30, 2014	508,693	13,373	5,915	324,913	59,397	11,347	93,748
Balance, beginning of period at Dec. 31, 2014	512,444	13,373	5,915	324,913	64,374	10,111	93,758
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	22,253				22,216		37
Other comprehensive income (loss)	(2,058)					(2,058)
Balance, end of period at Sep. 30, 2015	$ 532,639	$ 13,373	$ 5,915	$ 324,913	$ 86,590	$ 8,053	$ 93,795