Segment Information - Schedule of Information Concerning Company's Principal Geographic Areas (Detail) (USD $)	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
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues	$ 40,234,000	$ 40,312,000	$ 39,241,000	$ 39,075,000	$ 35,080,000	$ 38,429,000	$ 35,167,000	$ 35,001,000	$ 158,862,000	$ 143,677,000	$ 138,302,000
Total long-lived assets	242,743,000				164,339,000				242,743,000	164,339,000
Total assets	352,823,000				251,416,000				352,823,000	251,416,000
Reportable Geographical Components
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues									158,862,000	143,677,000	138,302,000
Total long-lived assets	174,952,000				164,339,000				174,952,000	164,339,000
Total assets	352,823,000				251,416,000				352,823,000	251,416,000
Reportable Geographical Components | UNITED STATES
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues									124,686,000	106,282,000	102,504,000
Total long-lived assets	170,922,000				159,970,000				170,922,000	159,970,000
Total assets	345,461,000				243,463,000				345,461,000	243,463,000
Reportable Geographical Components | CANADA
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues									25,168,000	24,503,000	24,284,000
Total long-lived assets	4,030,000				4,332,000				4,030,000	4,332,000
Total assets	6,133,000				6,635,000				6,133,000	6,635,000
Reportable Geographical Components | Other International
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues									9,008,000	12,892,000	11,514,000
Total long-lived assets					37,000					37,000
Total assets	$ 1,229,000				$ 1,318,000				$ 1,229,000	$ 1,318,000