PARENT COMPANY ONLY FINANCIAL INFORMATION (CONDENSED BALANCE SHEETS) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Assets
Cash deposited in First Bank (unrestricted cash)	$ 114,841	$ 101,822
Other assets	67,996	73,026
Total assets	6,509,126	6,608,913	7,378,128
Liabilities and Stockholders' Equity
Subordinated debentures	354,133	354,057	353,981
Accrued expenses and other liabilities	144,269	115,962
Total liabilities	6,209,167	6,345,242
First Banks, Inc. stockholders’ equity	206,304	169,719
Total liabilities and stockholders’ equity	6,509,126	6,608,913
Parent Company
Assets
Cash deposited in First Bank (unrestricted cash)	2,744	2,801
Cash deposited in unaffiliated financial institution (restricted cash)	0	2,008
Total cash	2,744	4,809
Investment in common securities - TRuPS	10,678	10,678
Investment in subsidiaries	657,838	586,899
Other assets	3,583	3,067
Total assets	674,843	605,453
Liabilities and Stockholders' Equity
Subordinated debentures	354,133	354,057
Derivative instruments	0	807
Accrued interest payable	47,878	33,179
Dividends payable	61,931	43,045
Accrued expenses and other liabilities	4,597	4,646
Total liabilities	468,539	435,734
First Banks, Inc. stockholders’ equity	206,304	169,719
Total liabilities and stockholders’ equity	$ 674,843	$ 605,453