Note 4 - Fair Value (Detail) - Changes in Level 3 Assets Measured at Fair Value on a Recurring Basis (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Total unrealized gains/(losses) included in other comprehensive income	$ (105)	$ 608
Fair Value, Inputs, Level 3 [Member]
Balance at beginning of year	21,870	16,914
Balance at March 31 of each year	22,035	16,628
Total realized and unrealized gains/(losses) included in income	0	0
Total unrealized gains/(losses) included in other comprehensive income	0	0
Purchases of securities	165	2,242
Sales of securities	0	0
Calls and maturities	0	(2,528)
Net transfers in/(out) of Level 3	$ 0	$ 0