Note 11 - Fair Value Measurements (Details) - Financial Assets and Liabilities Measured On a Non-recurring Basis - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Mar. 31, 2016		Mar. 31, 2015		Dec. 31, 2015		Dec. 31, 2014
Impaired loans by type:
Fair value measurement	$ 54,972				$ 58,889
Total losses/gains	238		$ 609		2,507		$ 4,596
Impaired Loans [Member]
Impaired loans by type:
Fair value measurement	34,029				39,685
Total losses/gains			204		1,550		3,958
Other Real Estate Owned [Member]
Impaired loans by type:
Fair value measurement	16,112	[1]			14,282	[2]
Total losses/gains	128	[1]	181	[1]	404	[2]	202	[2]
Investments in Venture Capital [Member]
Impaired loans by type:
Fair value measurement	4,831				4,922
Total losses/gains	$ 110		224		$ 553		436
Fair Value, Inputs, Level 1 [Member] | Other Real Estate Owned [Member]
Impaired loans by type:
Fair value measurement		[1]				[2]
Fair Value, Inputs, Level 2 [Member]
Impaired loans by type:
Fair value measurement	$ 11,906				$ 10,047
Fair Value, Inputs, Level 2 [Member] | Other Real Estate Owned [Member]
Impaired loans by type:
Fair value measurement	11,906	[1]			10,047	[2]
Fair Value, Inputs, Level 3 [Member]
Impaired loans by type:
Fair value measurement	43,066				48,842
Fair Value, Inputs, Level 3 [Member] | Impaired Loans [Member]
Impaired loans by type:
Fair value measurement	34,029				39,685
Fair Value, Inputs, Level 3 [Member] | Other Real Estate Owned [Member]
Impaired loans by type:
Fair value measurement	4,206	[1]			4,235	[2]
Fair Value, Inputs, Level 3 [Member] | Investments in Venture Capital [Member]
Impaired loans by type:
Fair value measurement	4,831				4,922
Commercial Portfolio Segment [Member]
Impaired loans by type:
Fair value measurement	2,493				6,317
Total losses/gains					806		17
Commercial Portfolio Segment [Member] | Fair Value, Inputs, Level 3 [Member]
Impaired loans by type:
Fair value measurement	2,493				6,317
Commercial Real Estate Portfolio Segment [Member]
Impaired loans by type:
Fair value measurement	19,565				20,359
Total losses/gains			56		598		3,914
Commercial Real Estate Portfolio Segment [Member] | Fair Value, Inputs, Level 3 [Member]
Impaired loans by type:
Fair value measurement	19,565				20,359
Residential Mortgage and Equity Lines Portfolio Segment [Member]
Impaired loans by type:
Fair value measurement	11,971				13,009
Total losses/gains			$ 148		146		$ 27
Residential Mortgage and Equity Lines Portfolio Segment [Member] | Fair Value, Inputs, Level 3 [Member]
Impaired loans by type:
Fair value measurement	$ 11,971				$ 13,009

[1] Other real estate owned balance of $27.3 million in the condensed consolidated balance sheet is net of estimated disposal costs.

[2] Other real estate owned balance of $24.7 million in the consolidated balance sheet is net of estimated disposal costs.