Note 12 - Fair Value (Details) - Fair Value Measurements (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013		Mar. 31, 2013	Dec. 31, 2012	Jun. 30, 2012		Mar. 31, 2012	Dec. 31, 2011
Trading securities:
Total trading securities	$ 15,451			$ 14,162
Securities available-for-sale:
CDOs	14,917	[1]	12,924	12,129	11,082	[1]	13,685	13,394
Total securities available-for-sale	1,223,486			1,082,403
Liabilities:
Derivative liabilities (2)	(1,730)			(2,270)
Fair Value, Inputs, Level 1 [Member]
Trading securities:
Money market funds	1,291			1,554
Mutual funds	14,160			12,608
Total trading securities	15,451			14,162
Securities available-for-sale:
Other equity securities	27,454			43
Total securities available-for-sale	27,454			43
Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale:
U.S. agency securities	503			508
CMOs	536,423			400,383
Other MBSs	126,772			122,900
Municipal securities	490,759			520,043
Corporate debt securities	15,107			15,339
Hedge fund investment	2,741			1,616
Other equity securities	8,810			9,442
Total securities available-for-sale	1,181,115			1,070,231
Derivative assets (1)	241
Liabilities:
Derivative liabilities (2)	1,971			2,270
Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale:
CDOs	14,917			12,129
Total securities available-for-sale	14,917			12,129
Mortgage servicing rights (1)	$ 1,352			$ 985

[1] There were no purchases, issuances, or settlements of CDOs during the periods presented. One CDO with a carrying value of zero was sold during the quarter ended June 30, 2013, resulting in a gain of $101,000.