Note 4 - Loans and Allowance for Credit Losses (Detail) - Recorded Investment In The Company's Loans And Leases (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
Loans And Leases Receivable Net Of Deferred Income	$ 2,548,024	$ 2,493,095	$ 2,186,940
Pass [Member] | Commercial Loan [Member]
Loans And Leases Receivable Net Of Deferred Income	532,391	495,072	454,373
Pass [Member] | Commercial Real Estate Investment [Member]
Loans And Leases Receivable Net Of Deferred Income	886,172	892,569	815,951
Pass [Member] | Commercial Real Estate Owner Occupied [Member]
Loans And Leases Receivable Net Of Deferred Income	281,632	275,864	254,405
Pass [Member] | Residential Mortgage [Member]
Loans And Leases Receivable Net Of Deferred Income	68,521	61,134	42,308
Pass [Member] | Home Equity Line of Credit [Member]
Loans And Leases Receivable Net Of Deferred Income	105,857	104,302	94,925
Pass [Member] | Consumer, Other [Member]
Loans And Leases Receivable Net Of Deferred Income	4,106	4,230	5,149
Pass [Member] | Construction Loans [Member]
Loans And Leases Receivable Net Of Deferred Income	523,535	508,166	387,770
Pass [Member]
Loans And Leases Receivable Net Of Deferred Income	2,402,214	2,341,337	2,054,881
Special Mention [Member] | Commercial Loan [Member]
Loans And Leases Receivable Net Of Deferred Income	32,832	34,821	29,019
Special Mention [Member] | Commercial Real Estate Investment [Member]
Loans And Leases Receivable Net Of Deferred Income	19,093	10,668	4,902
Special Mention [Member] | Commercial Real Estate Owner Occupied [Member]
Loans And Leases Receivable Net Of Deferred Income	15,480	13,270	18,423
Special Mention [Member] | Residential Mortgage [Member]
Loans And Leases Receivable Net Of Deferred Income	735	737
Special Mention [Member] | Home Equity Line of Credit [Member]
Loans And Leases Receivable Net Of Deferred Income	2,175	2,032
Special Mention [Member] | Consumer, Other [Member]
Loans And Leases Receivable Net Of Deferred Income	11	12
Special Mention [Member] | Construction Loans [Member]
Loans And Leases Receivable Net Of Deferred Income	17,566	17,862	32,631
Special Mention [Member]
Loans And Leases Receivable Net Of Deferred Income	87,892	79,402	84,975
Substandard [Member] | Commercial Loan [Member]
Loans And Leases Receivable Net Of Deferred Income	14,395	15,170	9,395
Substandard [Member] | Commercial Real Estate Investment [Member]
Loans And Leases Receivable Net Of Deferred Income	5,564	11,401	9,131
Substandard [Member] | Commercial Real Estate Owner Occupied [Member]
Loans And Leases Receivable Net Of Deferred Income	6,449	8,723	2,895
Substandard [Member] | Residential Mortgage [Member]
Loans And Leases Receivable Net Of Deferred Income			749
Substandard [Member] | Home Equity Line of Credit [Member]
Loans And Leases Receivable Net Of Deferred Income	538	510	512
Substandard [Member] | Consumer, Other [Member]
Loans And Leases Receivable Net Of Deferred Income		43	8
Substandard [Member] | Construction Loans [Member]
Loans And Leases Receivable Net Of Deferred Income	30,972	36,502	24,357
Substandard [Member]
Loans And Leases Receivable Net Of Deferred Income	57,918	72,349	47,047
Doubtful [Member] | Commercial Loan [Member]
Loans And Leases Receivable Net Of Deferred Income		7	37
Doubtful [Member]
Loans And Leases Receivable Net Of Deferred Income		7	37
Commercial Loan [Member]
Loans And Leases Receivable Net Of Deferred Income	579,618	545,070	492,824
Commercial Real Estate Investment [Member]
Loans And Leases Receivable Net Of Deferred Income	910,829	914,638	829,984
Commercial Real Estate Owner Occupied [Member]
Loans And Leases Receivable Net Of Deferred Income	303,561	297,857	275,723
Residential Mortgage [Member]
Loans And Leases Receivable Net Of Deferred Income	69,256	61,871	43,057
Home Equity Line of Credit [Member]
Loans And Leases Receivable Net Of Deferred Income	108,570	106,844	95,437
Consumer, Other [Member]
Loans And Leases Receivable Net Of Deferred Income	4,117	4,285	5,157
Construction Loans [Member]
Loans And Leases Receivable Net Of Deferred Income	$ 572,073	$ 562,530	$ 444,758