Note 21 - Variable Interest Entities ("VIE"s) (Detail) - Variable Interest Entities (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
First Midwest Capital Trust 1 (“FMCT”):
Number of VIEs	1	1
Carrying Amount of Assets	$ 62,128	$ 87,783
Maximum Exposure to Loss	62,128	87,783
FMTC I Principal balance of debentures issued by the company [Member]
First Midwest Capital Trust 1 (“FMCT”):
Carrying Amount of Assets	61,770	87,277
Maximum Exposure to Loss	61,770	87,277
FMTC I Related interest receivable [Member]
First Midwest Capital Trust 1 (“FMCT”):
Carrying Amount of Assets	358	506
Maximum Exposure to Loss	358	506
Interest in trust-preferred capital securities issuances [Member]
First Midwest Capital Trust 1 (“FMCT”):
Number of VIEs	2	1
Carrying Amount of Assets	6,393	32
Maximum Exposure to Loss	6,064	31
Investment in low-income housing tax credit partnerships [Member]
First Midwest Capital Trust 1 (“FMCT”):
Number of VIEs	9	12
Carrying Amount of Assets	713	1,066
Maximum Exposure to Loss	$ 713	$ 1,011