Note 3 - Loans and Allowance for Loan Losses (Details) - Activity in Allowance for Loan Losses and the Recorded Investments in Loans - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for loan losses	$ (500,000)	$ (400,000)	$ (1,500,000)	$ (3,000,000)
Loans	2,217,388,000		2,217,388,000		$ 2,089,277,000
Originated Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans	1,519,710,000		1,519,710,000
Loans: individually evaluated for impairment	19,047,000		19,047,000
Loans: collectively evaluated for impairment	1,500,663,000		1,500,663,000
Originated Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses	15,740,000	20,856,000	19,299,000	22,821,000
Allowance for loan losses	15,837,000	20,374,000	15,837,000	20,374,000
Allowance for loan losses: individually evaluated for impairment	1,827,000	11,364,000	1,827,000	11,364,000
Allowance for loan losses: collectively evaluated for impairment	14,010,000	9,010,000	14,010,000	9,010,000
Provision for loan losses	(93,000)	(400,000)	(1,194,000)	(3,000,000)
Charge-offs	(46,000)	(345,000)	(4,839,000)	(1,036,000)
Recoveries	236,000	263,000	2,571,000	1,589,000
Loans	1,519,710,000	1,186,713,000	1,519,710,000	1,186,713,000	1,246,116,000
Loans: individually evaluated for impairment		52,216,000		52,216,000
Loans: collectively evaluated for impairment		1,134,497,000		1,134,497,000
Acquired Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses	821,000		742,000
Allowance for loan losses	282,000		282,000
Provision for loan losses	(407,000)		(306,000)
Charge-offs	(136,000)		(174,000)
Recoveries	4,000		20,000
Loans	697,678,000		697,678,000		843,161,000
Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans	1,877,620,000		1,877,620,000		1,715,303,000
Commercial Portfolio Segment [Member] | Originated Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans	1,402,320,000		1,402,320,000
Loans: individually evaluated for impairment	17,835,000		17,835,000
Loans: collectively evaluated for impairment	1,384,485,000		1,384,485,000
Commercial Portfolio Segment [Member] | Originated Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses	13,992,000	19,107,000	17,736,000	20,455,000
Allowance for loan losses	14,201,000	18,712,000	14,201,000	18,712,000
Allowance for loan losses: individually evaluated for impairment	1,657,000	10,485,000	1,657,000	10,485,000
Allowance for loan losses: collectively evaluated for impairment	12,544,000	8,227,000	12,544,000	8,227,000
Provision for loan losses	9,000	(473,000)	(1,641,000)	(2,251,000)
Charge-offs	0	(24,000)	(4,276,000)	(708,000)
Recoveries	200,000	102,000	2,382,000	1,216,000
Loans	1,402,320,000	1,103,802,000	1,402,320,000	1,103,802,000	1,153,189,000
Loans: individually evaluated for impairment		48,870,000		48,870,000
Loans: collectively evaluated for impairment		1,054,932,000		1,054,932,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses	561,000		681,000
Allowance for loan losses	85,000		85,000
Provision for loan losses	(389,000)		(479,000)
Charge-offs	(87,000)		(118,000)
Recoveries	0		1,000
Loans	475,300,000		475,300,000		562,114,000
Retail Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans	339,768,000		339,768,000		373,974,000
Retail Portfolio Segment [Member] | Originated Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans	117,390,000		117,390,000
Loans: individually evaluated for impairment	1,212,000		1,212,000
Loans: collectively evaluated for impairment	116,178,000		116,178,000
Retail Portfolio Segment [Member] | Originated Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses	1,714,000	1,774,000	1,487,000	2,358,000
Allowance for loan losses	1,691,000	1,677,000	1,691,000	1,677,000
Allowance for loan losses: individually evaluated for impairment	170,000	879,000	170,000	879,000
Allowance for loan losses: collectively evaluated for impairment	1,521,000	798,000	1,521,000	798,000
Provision for loan losses	(13,000)	63,000	578,000	(726,000)
Charge-offs	(46,000)	(321,000)	(563,000)	(328,000)
Recoveries	36,000	161,000	189,000	373,000
Loans	117,390,000	82,911,000	117,390,000	82,911,000	92,927,000
Loans: individually evaluated for impairment		3,346,000		3,346,000
Loans: collectively evaluated for impairment		79,565,000		79,565,000
Retail Portfolio Segment [Member] | Acquired Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses	260,000		61,000
Allowance for loan losses	197,000		197,000
Provision for loan losses	(18,000)		173,000
Charge-offs	(49,000)		(56,000)
Recoveries	4,000		19,000
Loans	222,378,000		222,378,000		$ 281,047,000
Unallocated Financing Receivables [Member] | Originated Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses	34,000	(25,000)	76,000	8,000
Allowance for loan losses	(55,000)	(15,000)	(55,000)	(15,000)
Allowance for loan losses: individually evaluated for impairment	0	0	0	0
Allowance for loan losses: collectively evaluated for impairment	(55,000)	(15,000)	(55,000)	(15,000)
Provision for loan losses	(89,000)	10,000	(131,000)	(23,000)
Charge-offs	0	0	0	0
Recoveries	0	$ 0	0	$ 0
Unallocated Financing Receivables [Member] | Acquired Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses	0		0
Allowance for loan losses	0		0
Provision for loan losses	0		0
Charge-offs	0		0
Recoveries	$ 0		$ 0