Note 3. Securities (Detail) - Securities Held to Maturity with Unrealized Losses (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Obligations of states and
Less than 12 months fair value	$ 2,927	$ 664
Less than 12 months unrecognized loss	(37)	(21)
12 months or more fair value	1,595	3,557
12 months or more unrecognized loss	(33)	(538)
Fair value	4,522	4,221
Unrecognized loss	(70)	(559)
US States and Political Subdivisions Debt Securities [Member]
Obligations of states and
Less than 12 months fair value	2,927	664
Less than 12 months unrecognized loss	(37)	(21)
12 months or more fair value	1,595	3,557
12 months or more unrecognized loss	(33)	(538)
Fair value	4,522	4,221
Unrecognized loss	$ (70)	$ (559)