Note 7 - Investment Securities (Detail) (USD $) In Thousands, unless otherwise specified				3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 Corporate Debt Securities [Member]	Mar. 31, 2013 AFS Gross Unrealized Losses [Member] Loss Increase [Member]	Mar. 31, 2013 AFS Gross Unrealized Losses [Member]	Mar. 31, 2013 AFS Continuous Unrealized Loss Position 12 Months Or Longer [Member] Loss Decrease [Member]	Mar. 31, 2013 AFS Continuous Unrealized Loss Position 12 Months Or Longer [Member]	Mar. 31, 2013 Single Issuer Corporate Debt Security [Member]
Available-for-sale Securities, Gross Unrealized Losses	$ 1,500
Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss) before Taxes					(127)		210
Percent Change Unrealized Loss Investment Securities				9.40%		24.50%
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	646		645
Available-for-sale Securities, Amortized Cost Basis	$ 556,258	$ 558,630						$ 5,200