Note 4 - Loans and Allowance for Credit Losses (Detail) - Loans, Net Of Unamortized Net Deferred Fees (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012		Mar. 31, 2012
Amount	$ 2,548,024		$ 2,493,095		$ 2,186,940
Percent	100.00%		100.00%		100.00%
Less: Allowance for Credit Losses	(38,811)		(37,492)		(31,875)
Net loans	2,509,213		2,455,603		2,155,065
Commercial Loan [Member] | Secured Loan [Member]
Amount	579,618		545,070		492,824
Percent	23.00%		22.00%		23.00%
Commercial Loan [Member]
Amount	579,618		545,070		492,824
Less: Allowance for Credit Losses					(8,537)
Commercial Real Estate Investment [Member] | Secured Loan [Member]
Amount	910,829	[1]	914,638	[1]	829,984	[1]
Percent	36.00%	[1]	37.00%	[1]	38.00%	[1]
Commercial Real Estate Investment [Member]
Amount	910,829		914,638		829,984
Less: Allowance for Credit Losses					(8,145)
Commercial Real Estate Owner Occupied [Member] | Secured Loan [Member]
Amount	303,561		297,857		275,723
Percent	12.00%		12.00%		13.00%
Commercial Real Estate Owner Occupied [Member]
Amount	303,561		297,857		275,723
Less: Allowance for Credit Losses					(2,146)
Residential Mortgage [Member] | Secured Loan [Member]
Amount	69,256		61,871		43,057
Percent	3.00%		3.00%		2.00%
Residential Mortgage [Member]
Amount	69,256		61,871		43,057
Home Equity Line of Credit [Member] | Secured Loan [Member]
Amount	108,570		106,844		95,437
Percent	4.00%		4.00%		4.00%
Home Equity Line of Credit [Member]
Amount	108,570		106,844		95,437
Less: Allowance for Credit Losses					(1,329)
Consumer, Other [Member] | Secured Loan [Member]
Amount	4,117		4,285		5,157
Consumer, Other [Member]
Amount	4,117		4,285		5,157
Less: Allowance for Credit Losses					(58)
Secured Loan [Member] | Construction Loans [Member]
Amount	538,071	[1]	533,722	[1]	417,346	[1]
Percent	21.00%	[1]	21.00%	[1]	19.00%	[1]
Secured Loan [Member] | Construction - C&I (owner occupied) [Member]
Amount	34,002	[1]	28,808	[1]	27,412	[1]
Percent	1.00%	[1]	1.00%	[1]	1.00%	[1]
Construction Loans [Member]
Amount	572,073		562,530		444,758
Less: Allowance for Credit Losses					$ (11,660)

[1] Includes loans for land acquisition and development.