Note 5 - Loans and Allowance for Credit Losses (Details) - Allowance for Credit Losses by Portfolio Segment - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Allowance for credit losses:
Balance at beginning of period	$ 48,921	$ 43,552	$ 46,075	$ 40,921
Loans charged-off	(1,962)	(1,237)	(6,170)	(4,052)
Recoveries of loans previously charged-off	99	528	372	906
Net loan charged-off	(1,863)	(709)	(5,798)	(3,146)
Provision for credit losses	3,262	2,111	10,043	7,179
Ending balance	50,320	44,954	50,320	44,954
Allowance for credit losses:
Individually evaluated for impairment	4,227	8,013	4,227	8,013
Collectively evaluated for impairment	46,093	36,941	46,093	36,941
Ending balance-Allowance for credit losses	50,320	44,954	50,320	44,954	$ 46,075
Commercial Portfolio Segment [Member]
Allowance for credit losses:
Balance at beginning of period	12,911	11,413	13,222	9,780
Loans charged-off	(1,388)	(317)	(4,693)	(1,968)
Recoveries of loans previously charged-off	60	519	135	802
Net loan charged-off	(1,328)	202	(4,558)	(1,166)
Provision for credit losses	57	1,558	2,976	4,559
Ending balance	11,640	13,173	11,640	13,173
Allowance for credit losses:
Individually evaluated for impairment	2,312	4,409	2,312	4,409
Collectively evaluated for impairment	9,328	8,764	9,328	8,764
Ending balance-Allowance for credit losses	11,640	13,173	11,640	13,173
Income Producing Portfolio Segment [Member]
Allowance for credit losses:
Balance at beginning of period	12,411	10,745	11,442	10,359
Loans charged-off	(254)	(22)	(651)	(22)
Recoveries of loans previously charged-off	8		26	4
Net loan charged-off	(246)	(22)	(625)	(18)
Provision for credit losses	1,550	478	2,898	860
Ending balance	13,715	11,201	13,715	11,201
Allowance for credit losses:
Individually evaluated for impairment	827	578	827	578
Collectively evaluated for impairment	12,888	10,623	12,888	10,623
Ending balance-Allowance for credit losses	13,715	11,201	13,715	11,201
Owner Occupied Portfolio Segment [Member]
Allowance for credit losses:
Balance at beginning of period	3,113	3,273	2,954	3,899
Loans charged-off				(35)
Recoveries of loans previously charged-off			2	7
Net loan charged-off			2	(28)
Provision for credit losses	(13)	42	144	(556)
Ending balance	3,100	3,315	3,100	3,315
Allowance for credit losses:
Individually evaluated for impairment	400	1,330	400	1,330
Collectively evaluated for impairment	2,700	1,985	2,700	1,985
Ending balance-Allowance for credit losses	3,100	3,315	3,100	3,315
Residential Portfolio Segment [Member]
Allowance for credit losses:
Balance at beginning of period	1,082	958	1,259	944
Loans charged-off		(48)		(138)
Recoveries of loans previously charged-off	2		5
Net loan charged-off	2	(48)	5	(138)
Provision for credit losses	(18)	70	(198)	174
Ending balance	1,066	980	1,066	980
Allowance for credit losses:
Collectively evaluated for impairment	1,066	980	1,066	980
Ending balance-Allowance for credit losses	1,066	980	1,066	980
Construction Portfolio Segment [Member]
Allowance for credit losses:
Balance at beginning of period	17,633	15,487	15,625	13,934
Loans charged-off		(620)		(1,426)
Recoveries of loans previously charged-off	10	6	114	77
Net loan charged-off	10	(614)	114	(1,349)
Provision for credit losses	1,281	(237)	3,185	2,051
Ending balance	18,924	14,636	18,924	14,636
Allowance for credit losses:
Individually evaluated for impairment	350	1,478	350	1,478
Collectively evaluated for impairment	18,574	13,158	18,574	13,158
Ending balance-Allowance for credit losses	18,924	14,636	18,924	14,636
Home Equity Portfolio Segment [Member]
Allowance for credit losses:
Balance at beginning of period	1,496	1,331	1,469	1,871
Loans charged-off	(225)	(230)	(644)	(379)
Recoveries of loans previously charged-off	1	2	5	8
Net loan charged-off	(224)	(228)	(639)	(371)
Provision for credit losses	334	259	776	(138)
Ending balance	1,606	1,362	1,606	1,362
Allowance for credit losses:
Individually evaluated for impairment	338	218	338	218
Collectively evaluated for impairment	1,268	1,144	1,268	1,144
Ending balance-Allowance for credit losses	1,606	1,362	1,606	1,362
Other Consumer Portfolio Segment [Member]
Allowance for credit losses:
Balance at beginning of period	275	345	104	134
Loans charged-off	(95)		(182)	(84)
Recoveries of loans previously charged-off	18	1	85	8
Net loan charged-off	(77)	1	(97)	(76)
Provision for credit losses	71	(59)	262	229
Ending balance	269	287	269	287
Allowance for credit losses:
Collectively evaluated for impairment	269	287	269	287
Ending balance-Allowance for credit losses	$ 269	$ 287	$ 269	$ 287