Note 8 - Goodwill and Other Intangible Assets (Detail) - Core Deposit Intangibles (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Balance at the beginning of the year	$ 34,318	$ 42,832	$ 36,591
Balance at the beginning of the year	16,145	22,276	17,998
Balance at the beginning of the year	18,173	20,556	18,593
Additions	781	1,419	6,242
Amortization expense	3,372	3,802	4,279
Amortization expense	(3,372)	(3,802)	(4,279)
Fully amortized assets	(1,324)	(9,933)	(1)
Fully amortized assets	(1,324)	(9,933)	(1)
Balance at the end of the year	33,775	34,318	42,832
Balance at the end of the year	18,193	16,145	22,276
Balance at the end of the year	$ 15,582	$ 18,173	$ 20,556
Weighted-average remaining life (in years)	6 years 146 days	6 years 328 days	7 years 109 days
Minimum [Member]
Estimated useful lives (in years)	3 years 109 days	3 years 109 days	3 years 109 days
Maximum [Member]
Estimated useful lives (in years)	12 years 292 days	12 years 219 days	12 years 219 days