CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Statement Of Partners Capital [Abstract]
Net income	$ 3,043	$ 2,485	$ 5,251	$ 4,530
Other comprehensive income (loss):
Foreign currency	153	(204)	(628)	(86)
Other comprehensive income (loss)	153	(204)	(628)	(86)
Comprehensive income	$ 3,196	$ 2,281	$ 4,623	$ 4,444