Note Q - Supplemental Information (Details) - Allowance for Doubtful Accounts (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Allowance for Doubtful Accounts [Abstract]
Balance at beginning of period	$ 1,753	$ 1,448	$ 1,746
Bad debt expense	272	112	336
Net recoveries (write-offs)	(138)	193	(634)
Balance at end of period	$ 1,887	$ 1,753	$ 1,448