Note 4 - Fair Value Measurements (Detail) - Assets Measured on a Recurring Basis (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Assets Measured on a Recurring Basis:
Assets Measured on a Recurring Basis	$ 173,446	$ 193,977
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Assets Measured on a Recurring Basis:
Assets Measured on a Recurring Basis	13,572	31,933
US Government Agencies Debt Securities [Member]
Assets Measured on a Recurring Basis:
Assets Measured on a Recurring Basis	13,572	31,933
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Assets Measured on a Recurring Basis:
Assets Measured on a Recurring Basis	88,587	88,400
US States and Political Subdivisions Debt Securities [Member]
Assets Measured on a Recurring Basis:
Assets Measured on a Recurring Basis	88,587	88,400
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Fair Value, Inputs, Level 2 [Member]
Assets Measured on a Recurring Basis:
Assets Measured on a Recurring Basis	64,274	65,573
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Assets Measured on a Recurring Basis:
Assets Measured on a Recurring Basis	64,274	65,573
Mortgage-backed Securities, Issued by Private Enterprises [Member] | Fair Value, Inputs, Level 2 [Member]
Assets Measured on a Recurring Basis:
Assets Measured on a Recurring Basis	6,262	7,321
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Assets Measured on a Recurring Basis:
Assets Measured on a Recurring Basis	6,262	7,321
Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Assets Measured on a Recurring Basis:
Assets Measured on a Recurring Basis	172,695	193,227
Debt Securities [Member]
Assets Measured on a Recurring Basis:
Assets Measured on a Recurring Basis	172,695	193,227
Equity Securities in Financial Institutions [Member] | Fair Value, Inputs, Level 1 [Member]
Assets Measured on a Recurring Basis:
Assets Measured on a Recurring Basis	5	5
Equity Securities in Financial Institutions [Member] | Fair Value, Inputs, Level 2 [Member]
Assets Measured on a Recurring Basis:
Assets Measured on a Recurring Basis	746	745
Equity Securities in Financial Institutions [Member]
Assets Measured on a Recurring Basis:
Assets Measured on a Recurring Basis	751	750
Fair Value, Inputs, Level 1 [Member]
Assets Measured on a Recurring Basis:
Assets Measured on a Recurring Basis	5	5
Fair Value, Inputs, Level 2 [Member]
Assets Measured on a Recurring Basis:
Assets Measured on a Recurring Basis	$ 173,441	$ 193,972