Shareholders' Equity - Summary of Stock Option (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Equity [Abstract]
Beginning balance of outstanding shares	1,807	1,244	1,174
Granted, Shares	280	923	163
Forfeitures, Shares	(121)	(44)	(52)
Exercised, Shares	(239)	(316)	(41)
Ending balance of outstanding, shares	1,727	1,807	1,244	1,174
Exercisable, Shares	655	557	614
Beginning Balance of Outstanding Weighted Average Exercise Price	$ 9.05	$ 5.18	$ 4.74
Granted, Weighted Average Exercise Price	$ 13.78	$ 12.72	$ 7.96
Forfeitures, Weighted Average Exercise Price	$ 12.45	$ 9.83	$ 5.87
Exercised, Weighted Average Exercise Price	$ 5.18	$ 4.41	$ 5.95
Ending Balance of Outstanding Weighted Average Exercise Price	$ 10.12	$ 9.05	$ 5.18	$ 4.74
Exercisable, Weighted Average Exercise Price	$ 5.02	$ 5.76	$ 5.36
Outstanding, Weighted Average Remaining Contractual Term	8 years 2 months 12 days	7 years 8 months 12 days	6 years 9 months 18 days	7 years 3 months 18 days
Outstanding, Weighted Average Remaining Contractual Term	8 years 2 months 12 days	7 years 8 months 12 days	6 years 9 months 18 days	7 years 3 months 18 days
Exercisable, Weighted Average Remaining Contractual Term	5 years 9 months 18 days	5 years 2 months 12 days	5 years 10 months 24 days
Outstanding, Aggregate Intrinsic Value	$ 12,830	$ 6,198
Outstanding, Aggregate Intrinsic Value	9,390	12,830	6,198
Exercisable, Aggregate Intrinsic Value	$ 5,332	$ 5,786	$ 3,086