Note N - Accumulated Other Comprehensive Income - Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Losses (gains) reclassified from accumulated other comprehensive income (loss)	$ (62)		$ (85)
Net current period other comprehensive income (loss)	146	$ 110	461	$ 793
Ending balance	(1,391)		(1,391)
Beginning balance	(1,537)		(1,852)
Other comprehensive income before reclassifications	208		546
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Losses (gains) reclassified from accumulated other comprehensive income (loss)	11		58
Net current period other comprehensive income (loss)	167		418
Ending balance	(683)		(683)
Beginning balance	(850)		(1,101)
Other comprehensive income before reclassifications	156		360
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Losses (gains) reclassified from accumulated other comprehensive income (loss)	(78)		(153)
Net current period other comprehensive income (loss)	(29)		39
Ending balance	48		48
Beginning balance	77		9
Other comprehensive income before reclassifications	49		192
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Losses (gains) reclassified from accumulated other comprehensive income (loss)	5		10
Net current period other comprehensive income (loss)	5		10
Ending balance	(445)		(445)
Beginning balance	(450)		(455)
Other comprehensive income before reclassifications
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Losses (gains) reclassified from accumulated other comprehensive income (loss)
Net current period other comprehensive income (loss)	3		(6)
Ending balance	(311)		(311)
Beginning balance	(314)		(305)
Other comprehensive income before reclassifications	$ 3		$ (6)