PARENT COMPANY ONLY FINANCIAL INFORMATION (Condensed Balance Sheets) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Assets
Cash deposited in First Bank	$ 100,349	$ 92,369
Deferred income taxes	312,575	315,881
Total assets	5,935,519	5,918,983	6,509,126
Liabilities and Stockholders' Equity
Subordinated debentures	354,286	354,210	354,133
Accrued expenses and other liabilities	113,682	191,082
Total liabilities	5,423,075	5,430,727
First Banks, Inc. stockholders’ equity	418,686	394,422
Total liabilities and stockholders’ equity	5,935,519	5,918,983
First Banks, Inc. Parent Company [Member]
Assets
Cash deposited in First Bank	21,616	1,864
Investment in common securities - TRuPS	10,678	10,678
Investment in subsidiaries	778,306	838,489
Deferred income taxes	42,445	41,095
Accrued interest receivable - TRuPS	11	1,887
Total assets	853,056	894,013
Liabilities and Stockholders' Equity
Subordinated debentures	354,286	354,210
Accrued interest payable - TRuPS	374	62,855
Dividends payable	77,800	77,800
Accrued expenses and other liabilities	1,910	4,726
Total liabilities	434,370	499,591
First Banks, Inc. stockholders’ equity	418,686	394,422
Total liabilities and stockholders’ equity	$ 853,056	$ 894,013