Stock-based Compensation - Summary of Stock Appreciation Rights (Detail) - Jun. 30, 2015 - USD ($) $ / shares in Units, $ in Thousands	Total
Time-Based Stock Appreciation Rights [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Outstanding, Beginning Balance	3,853,367
Number of Shares, Granted	270,000
Number of Shares, Exercised	(106,950)
Number of Shares, Forfeited or expired	(50,000)
Number of Shares, Outstanding, Ending Balance	3,966,417
Number of Shares, Exercisable	3,318,417
Number of Shares, Vested and expected to vest	3,966,417
Weighted-Average Exercise Price, Outstanding, Beginning Balance	$ 4.53
Weighted-Average Exercise Price, Granted	6.23
Weighted-Average Exercise Price, Exercised	4.15
Weighted-Average Exercise Price, Forfeited or expired	4.83
Weighted-Average Exercise Price, Outstanding, Ending Balance	4.65
Weighted-Average Exercise Price, Exercisable	4.24
Weighted-Average Exercise Price, Vested and expected to vest	$ 4.65
Weighted-Average Remaining Contractual Term, Outstanding	6 years
Weighted-Average Remaining Contractual Term, Exercisable	5 years 3 months 7 days
Weighted-Average Remaining Contractual Term, Vested and expected to vest	6 years
Aggregate Intrinsic Value, Outstanding, Ending balance	$ 8,608
Aggregate Intrinsic Value, Exercisable	8,633
Aggregate Intrinsic Value, Vested and expected to vest	$ 8,608
Performance-Based Stock Appreciation Rights [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Outstanding, Beginning Balance	786,034
Number of Shares, Granted	8,000
Number of Shares, Exercised	(10,300)
Number of Shares, Forfeited or expired	(160)
Number of Shares, Outstanding, Ending Balance	783,574
Number of Shares, Exercisable	779,574
Number of Shares, Vested and expected to vest	783,574
Weighted-Average Exercise Price, Outstanding, Beginning Balance	$ 5.51
Weighted-Average Exercise Price, Granted	5.65
Weighted-Average Exercise Price, Exercised	2.78
Weighted-Average Exercise Price, Forfeited or expired	5.65
Weighted-Average Exercise Price, Outstanding, Ending Balance	5.55
Weighted-Average Exercise Price, Exercisable	5.55
Weighted-Average Exercise Price, Vested and expected to vest	$ 5.55
Weighted-Average Remaining Contractual Term, Outstanding	4 years 10 months 24 days
Weighted-Average Remaining Contractual Term, Exercisable	4 years 10 months 13 days
Weighted-Average Remaining Contractual Term, Vested and expected to vest	4 years 10 months 24 days
Aggregate Intrinsic Value, Outstanding, Ending balance	$ 1,925
Aggregate Intrinsic Value, Exercisable	1,921
Aggregate Intrinsic Value, Vested and expected to vest	$ 1,925