Note 4 - Investment Securities (Detail) - Securities Classified by Contractual Maturity (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Total	$ 291,574	$ 271,729
Total	296,837	403,218
Total		386,408
US Treasury Securities [Member]
Available for sale securities amortized cost	6,387
Available for sale securities fair value	6,386
Total	6,387
Collateral Mortgage Obligations Federal National Mortgage Association [Member]
Held to maturity securities amortized cost		2,051
Held to maturity securities fair value		2,139
Collateral Mortgage Obligation Federal Home Loan Mortgage Corporation [Member]
Available for sale securities amortized cost	19,615
Available for sale securities fair value	19,632
Held to maturity securities amortized cost		3,525
Held to maturity securities fair value		3,670
Total	19,615	21,642
Collateral Mortgage Obligation Government National Mortgage Association [Member]
Available for sale securities amortized cost	3,293
Available for sale securities fair value	3,291
Total	3,293	5,666
Federal National Mortgage Association [Member]
Available for sale securities amortized cost	1,860
Available for sale securities fair value	1,978
Held to maturity securities amortized cost		32,731
Held to maturity securities fair value		35,585
Total	1,860	2,137
Federal Home Loan Mortgage Corporation [Member]
Available for sale securities amortized cost	20
Available for sale securities fair value	19
Held to maturity securities amortized cost		15,768
Held to maturity securities fair value		17,005
Total	20	38
Government National Mortgage Association [Member]
Available for sale securities amortized cost	85
Available for sale securities fair value	86
Held to maturity securities amortized cost		3,385
Held to maturity securities fair value		3,944
Total	85	98
Residential Mortgage Backed Securities [Member]
Available for sale securities amortized cost	24,873
Available for sale securities fair value	25,006
Held to maturity securities amortized cost		57,460
Held to maturity securities fair value		62,343
Total	24,873	29,581
Federal National Mortgage Association Agency Notes [Member]
Total	650	501
Available for sale securities due after 1 year but within 5 years amortized cost	650
Available for sale securities due after 1 year but within 5 years fair value	651
Held to maturity securities due after 1 year but within 5 years amortized cost		10,000
Held to maturity securities due after 1 year but within 5 years fair value		10,007
Held to maturity securities due after 10 years carrying value		85,977
Held to maturity securities due after 10 years fair value		85,991
Federal Home Loan Bank Agency Notes [Member]
Total	500	101
Available for sale securities due after 1 year but within 5 years amortized cost	250
Available for sale securities due after 1 year but within 5 years fair value	251
Available for sale securities due after 5 years but within 10 years carrying value	250
Available for sale securities due after 5 years but within 10 years fair value	250
Held to maturity securities due after 10 years carrying value		15,000
Held to maturity securities due after 10 years fair value		15,021
Federal Home Loan Mortgage Corporation Agency Notes [Member]
Total	75	376
Available for sale securities due after 1 year but within 5 years amortized cost	75
Available for sale securities due after 1 year but within 5 years fair value	79
Held to maturity securities due after 10 years carrying value		81,989
Held to maturity securities due after 10 years fair value		82,015
Obligations of U.S. Government Corporations and Government Sponsored Enterprises [Member]
Available for sale securities amortized cost	26,098
Available for sale securities fair value	26,237
Held to maturity securities amortized cost		250,426
Held to maturity securities fair value		255,377
Total	26,098	30,810
US States and Political Subdivisions Debt Securities [Member]
Available for sale securities amortized cost	16,499
Available for sale securities fair value	17,923
Held to maturity securities amortized cost		135,982
Held to maturity securities fair value		147,841
Held to maturity securities due after 1 year but within 5 years amortized cost		155
Held to maturity securities due after 1 year but within 5 years fair value		167
Available for sale securities due after 5 years but within 10 years carrying value	3,355
Available for sale securities due after 5 years but within 10 years fair value	3,632
Held to maturity securities due after 5 years but within 10 years carrying value		9,267
Held to maturity securities due after 5 years but within 10 years fair value		10,232
Available for sale securities due after 10 years amortized cost	13,144
Available for sale securities due after 10 years fair value	14,291
Held to maturity securities due after 10 years carrying value		126,560
Held to maturity securities due after 10 years fair value		137,442
Single Issuer Trust Preferred Securities [Member]
Available for sale securities amortized cost	37,875
Available for sale securities fair value	38,885
Total	37,875	28,506
Available for sale securities due within 1 year	7,724
Available for sale securities due within 1 year	7,673
Available for sale securities due after 10 years amortized cost	30,151
Available for sale securities due after 10 years fair value	31,212
Other Preferred Securities [Member]
Available for sale securities amortized cost	12,012
Available for sale securities fair value	11,953
Total	12,012
Available for sale securities due within 1 year	11,910
Available for sale securities due within 1 year	11,849
Available for sale securities due after 10 years amortized cost	102
Available for sale securities due after 10 years fair value	104
Corporate Debt Securities [Member]
Available for sale securities amortized cost	173,332
Available for sale securities fair value	174,418
Total	173,332	175,920
Due within 6 months	51,690
Due within 6 months	51,705
Due after 6 months but within 1 year	47,689
Due after 6 months but within 1 year	47,926
Due after 1 year but within 2 years	54,872
Due after 1 year but within 2 years	55,484
Due after 2 years but within 5 years	16,430
Due after 2 years but within 5 years	16,532
Available for sale securities due after 5 years but within 10 years carrying value	2,552
Available for sale securities due after 5 years but within 10 years fair value	2,664
Available for sale securities due after 10 years amortized cost	99
Available for sale securities due after 10 years fair value	107
Equity and Other Securities [Member]
Available for sale securities amortized cost	19,371
Available for sale securities fair value	21,035
Total	$ 19,371	$ 15,322