Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement of Comprehensive Income [Abstract]
Net income	$ 13,143	$ 18,072	$ 44,029	$ 51,824
Other comprehensive income (loss):
Foreign currency translation adjustments	1,670	1,196	(2,426)	(2,182)
Total other comprehensive income (loss)	1,670	1,196	(2,426)	(2,182)
Comprehensive income	$ 14,813	$ 19,268	$ 41,603	$ 49,642