Stock-Based Compensation - Summary of Company's Stock Option Plan Activity (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended						9 Months Ended		12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding Beginning, Number of Options	230,000	230,000	280,000	280,000	280,000	280,000	280,000	280,000	280,000
Exercised, Number of Options			(50,000)				(50,000)	0
Outstanding Ending, Number of Options	230,000	230,000	230,000	280,000	280,000	280,000	230,000	280,000	280,000	280,000
Exercisable Ending, Number of Options	230,000			270,000			230,000	270,000
Outstanding Beginning, Weighted Average Exercise price	$ 3.00	$ 3.00	$ 2.91	$ 2.91	$ 2.91	$ 2.91	$ 2.91	$ 2.91	$ 2.91
Exercised, Weighted-Average Exercise Price			$ 2.50
Outstanding Ending, Weighted-Average Exercise Price	$ 3.00	$ 3.00	$ 3.00	$ 2.91	$ 2.91	$ 2.91	$ 3.00	$ 2.91	$ 2.91	$ 2.91
Exercisable Ending , Weighted-Average Exercise Price	$ 3.00			$ 2.78			$ 3.00	$ 2.78
Outstanding, Weighted-Average Remaining Contractual Term	3 years 3 months 18 days	3 years 6 months	3 years 9 months 18 days	4 years 2 months 12 days	4 years 2 months 12 days	4 years 8 months 12 days			3 years 10 months 24 days	4 years 10 months 24 days
Exercisable Ending, Weighted-Average Remaining Contractual Term	3 years 3 months 18 days			4 years
Outstanding Beginning, Aggregate Intrinsic Value	$ 8,649	$ 7,683	$ 14,166		$ 6,816		$ 14,166
Outstanding Ending, Aggregate Intrinsic Value	7,589	8,649	7,683	10,621		6,816	7,589	10,621	14,166
Exercisable Ending, Aggregate Intrinsic Value	$ 7,589			$ 10,276			$ 7,589	$ 10,276