Note 5 - Covered Assets (Detail) - FDIC-Assisted Transactions (USD $) In Thousands, unless otherwise specified	12 Months Ended		26 Months Ended		20 Months Ended		17 Months Ended
	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2011 First DuPage Bank [Member]		Dec. 31, 2011 Peotone Bank and Trust Company [Member]		Dec. 31, 2011 Palos Bank and Trust Company [Member]
Total assets of acquired institution at acquisition date			$ 261,422		$ 129,447		$ 484,764	[1]
Bargain-purchase gains			13,071		4,303			[1]
Goodwill	7,941						2,591	[1]
Stated loss threshold		$ 2,500	$ 65,000				$ 117,000	[1]
Reimbursement rate (2):
Before stated loss threshold			80.00%	[2]	80.00%	[2]	70.00%	[1],[2]
After stated loss threshold			95.00%	[2]		[2]	80.00%	[1],[2]

[1] Assets acquired and goodwill amounts were adjusted based on additional information received in 2011 relating to the acquisition-date fair value of certain assets and liabilities acquired. Refer to Note 1, "Summary of Significant Accounting Policies," for further details of this adjustment.

[2] Represents the rate at which the FDIC will reimburse the Company for losses incurred.