CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement of Comprehensive Income [Abstract]
Net income	$ 16,570	$ 19,710	$ 23,044
Unrealized gain (loss) on marketable securities:
Unrealized holding gain arising during the period, net of tax effect of $0, $215, $115	0	336	180
Less: reclassification adjustment for gains included in net income,	0	(516)	0
Interest rate swap, net of tax effect of ($1,164), $696, $451	1,828	(1,093)	(708)
Foreign currency translation adjustment, net of tax effect of $5, $15, $44	297	(59)	(182)
Total other comprehensive income (loss)	2,125	(1,332)	(710)
Total comprehensive income	$ 18,695	$ 18,378	$ 22,334