Segment and Geographical Information - Schedule of Revenues Attributed to Geographic Location (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting, Revenue Reconciling Item [Line Items]
Total consolidated revenues	$ 53,065	$ 50,196	$ 51,020	$ 50,443	$ 52,743	$ 46,839	$ 48,235	$ 48,461	$ 204,724	$ 196,278	$ 197,711
UNITED STATES
Segment Reporting, Revenue Reconciling Item [Line Items]
Total consolidated revenues									134,951	130,476	133,824
International [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total consolidated revenues									$ 69,773	$ 65,802	$ 63,887