Note 4 - Loans and Allowance for Credit Losses (Details) - Recorded investment in loans evaluated for impairment (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012		Jun. 30, 2012
Allowance for credit losses:
Individually evaluated for impairment	$ 247		$ 2,752
Collectively evaluated for impairment	33,372		30,175
Total	33,619		32,927		34,216
Carrying value of loans:
Individually evaluated for impairment	26,076		29,023
Collectively evaluated for impairment	1,903,407		2,067,705
Purchased loans with evidence of credit deterioration	9,858		14,629
Total	1,939,341		2,111,357
Commercial [Member]
Allowance for credit losses:
Individually evaluated for impairment	100		1,865
Collectively evaluated for impairment	5,982		6,314
Total	6,082		8,179		7,974
Carrying value of loans:
Individually evaluated for impairment	2,496		5,153
Collectively evaluated for impairment	307,125		334,963
Total	309,621		340,116
Commercial Real Estate Loans [Member]
Allowance for credit losses:
Individually evaluated for impairment			134
Collectively evaluated for impairment	11,276		9,938
Total	11,276		10,072		9,915
Carrying value of loans:
Individually evaluated for impairment	4,421		4,161
Collectively evaluated for impairment	609,584		628,766
Total	614,005		632,927
Construction [Member]
Allowance for credit losses:
Collectively evaluated for impairment	605		484
Total	605		484		2,693
Carrying value of loans:
Collectively evaluated for impairment	8,015		7,984
Total	8,015		7,984
Residential Real Estate Loans [Member]
Allowance for credit losses:
Collectively evaluated for impairment	532		380
Total	532		380		602
Carrying value of loans:
Collectively evaluated for impairment	195,322		222,458
Total	195,322		222,458
Consumer Installment And Other [Member]
Allowance for credit losses:
Collectively evaluated for impairment	3,076		3,613
Total	3,076		3,613		3,415
Carrying value of loans:
Collectively evaluated for impairment	426,340		460,698
Total	426,340		460,698
Purchased Non-Covered Loans [Member]
Carrying value of loans:
Individually evaluated for impairment	3,990		3,029
Collectively evaluated for impairment	54,474		65,098
Purchased loans with evidence of credit deterioration	2,598		6,764
Total	61,062		74,891
Purchased Covered Loans [Member]
Allowance for credit losses:
Individually evaluated for impairment	147		753
Collectively evaluated for impairment	138		252
Total	285		1,005		240
Carrying value of loans:
Individually evaluated for impairment	15,169		16,680
Collectively evaluated for impairment	302,547		347,738
Purchased loans with evidence of credit deterioration	7,260		7,865
Total	324,976	[1]	372,283	[1]
Unallocated Financing Receivable [Member]
Allowance for credit losses:
Collectively evaluated for impairment	11,763		9,194
Total	$ 11,763		$ 9,194		$ 9,377

[1] Credit risk profile reflects internally assigned grade of purchased covered loans without regard to FDIC indemnification.