Note 4 - Investment Securities (Detail) - Maturities of Investment Portfolio (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Total investment securities	$ 294,770
Total investment securities	299,073
US Government Agencies Debt Securities [Member]
Due after one year through five years - amortized cost	517
Due after one year through five years - fair value	578
Total investment securities	578	583
US States and Political Subdivisions Debt Securities [Member]
Due under one year	690
Due under one year	702
Due after one year through five years - amortized cost	150
Due after one year through five years - fair value	150
Debt securities due after ten years - amortized cost	15,387
Debt securities due after ten years - fair value	16,824
Total investment securities	17,676	17,986
Residential Mortgage Backed Securities [Member]
Debt securities due after five years through ten years - amortized cost	31,685
Debt securities due after five years through ten years - fair value	31,848
Debt securities due after ten years - amortized cost	103,586
Debt securities due after ten years - fair value	106,147
Total investment securities	137,995	159,113
Commercial Mortgage Backed Securities [Member]
Debt securities due after five years through ten years - amortized cost	37,538
Debt securities due after five years through ten years - fair value	36,828
Total investment securities	36,828	0
All Other Debt Securities [Member]
Debt securities due after five years through ten years - amortized cost	500
Debt securities due after five years through ten years - fair value	415
Debt securities due after ten years - amortized cost	104,717
Debt securities due after ten years - fair value	105,581
Total investment securities	$ 105,996	$ 67,889