Note 6 - Accumulated Other Comprehensive Income - Changes in Accumulated Other Comprehensive Income (Loss) by Component, Net of Tax (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Balance		$ 119,863
Change in accounting principle, ASC 2016-01
Change in accounting principle, ASC 2018-02
Total other comprehensive income (loss)		(1,510)	$ (169)
Balance		120,152
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Balance	[1]	1,091	1,201
Other comprehensive income (loss) before reclassification	[1]	(1,510)	153
Change in accounting principle, ASC 2016-01	[1],[2]	(141)
Change in accounting principle, ASC 2018-02	[1],[2]	187
Total other comprehensive income (loss)	[1]	(1,464)	(169)
Balance	[1]	$ (373)	1,032
Amount reclassified from accumulated other comprehensive income	[1]		$ (322)

[1] All amounts are net of tax. Amounts in parentheses indicate debits to accumulated other comprehensive income.

[2] Reclassifications are the result of the adoption of ASUs 2016-01 and 2018-02 effective for the Company beginning January 1, 2018. The reclassifications are presented within the Consolidated Statement of Changes in Stockholders' Equity for the affected transitional periods.