Note 5 - Loans and Allowance for Credit Losses (Detail) - Changes in the carrying amount of impaired purchased loans (USD $) In Thousands	9 Months Ended	12 Months Ended	4 Months Ended	9 Months Ended
	Sep. 30, 2011 Purchased Covered Loans [Member]	Dec. 31, 2010 Purchased Covered Loans [Member]	Dec. 31, 2010 Purchased Non-Covered Loans [Member]	Sep. 30, 2011 Purchased Non-Covered Loans [Member]
Carrying amount at the beginning of the period	$ 33,556	$ 43,196	$ 37,639	$ 33,725
Reductions during the period	(14,096)	(9,640)	(3,914)	(15,241)
Carrying amount at the end of the period	$ 19,460	$ 33,556	$ 33,725	$ 18,484