Note 7 - Marketable Securities, Available-for-sale (Tables)

9 Months Ended

Sep. 30, 2017

Notes Tables

Schedule of Available-for-sale Securities Reconciliation [Table Text Block]

	September 30, 2017							December 31, 2016
	Amortized Cost		Gross Unrealized Losses			Estimated Fair Value		Amortized Cost		Gross Unrealized Losses			Estimated Fair Value
	(Dollars in thousands)
Type of security:
Municipal bond and metropolitan district securities	$	24,994	$	(465	)	$	24,529	$	18,563	$	(465	)	$	18,098

Investments Classified by Contractual Maturity Date [Table Text Block]

	September 30, 2017
	(Dollars in thousands)
Contractual maturity:
Maturing in one year or less	$	—
Maturing after three years		24,529
Total marketable securities, available-for-sale	$	24,529