Note 3 - Summary of Significant Accounting Policies (Detail) - Net Margin Collateral Posted (Held) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Net margin collateral posted (held)	$ (5,235)	[1]	$ (1,153)	[1]
Interest Rate Swap [Member]
Net margin collateral posted (held)	425	[1]	273	[1]
Interest Rate Swaption [Member]
Net margin collateral posted (held)	(5,431)	[1]	(1,426)	[1]
Securities (Assets) [Member]
Net margin collateral posted (held)	$ (229)	[1]		[1]

[1] See Note 6, "Fair Value of Financial Instruments" for additional discussion.