Stock-Based Compensation - Summary of Stock Appreciation Rights (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Time-Based Stock Appreciation Rights [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Outstanding, Beginning Balance	2,199,094
Number of Shares, Granted	0	0
Number of Shares, Exercised	(73,800)
Number of Shares, Outstanding, Ending Balance	2,125,294	2,199,094
Number of Shares, Exercisable	2,095,294
Number of Shares, Vested and expected to vest	2,125,294
Weighted-Average Exercise Price, Outstanding, Beginning Balance	$ 5.36
Weighted-Average Exercise Price, Exercised	2.76
Weighted-Average Exercise Price, Outstanding, Ending Balance	5.35	$ 5.36
Weighted-Average Exercise Price, Exercisable	5.43
Weighted-Average Exercise Price, Vested and expected to vest	$ 5.35
Weighted-Average Remaining Contractual Term, Outstanding	2 years 9 months 3 days
Weighted-Average Remaining Contractual Term, Exercisable	2 years 8 months 12 days
Weighted-Average Remaining Contractual Term, Vested and expected to vest	2 years 9 months 3 days
Aggregate Intrinsic Value, Outstanding	$ 1,432
Aggregate Intrinsic Value, Exercisable	1,477
Aggregate Intrinsic Value, Vested and expected to vest	$ 1,432
Performance-Based Stock Appreciation Rights [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Outstanding, Beginning Balance	233,496
Number of Shares, Granted	0	0	0
Number of Shares, Outstanding, Ending Balance	233,496	233,496
Number of Shares, Exercisable	233,496
Number of Shares, Vested and expected to vest	233,496
Weighted-Average Exercise Price, Outstanding, Beginning Balance	$ 6.02
Weighted-Average Exercise Price, Outstanding, Ending Balance	6.01	$ 6.02
Weighted-Average Exercise Price, Exercisable	6.01
Weighted-Average Exercise Price, Vested and expected to vest	$ 6.01
Weighted-Average Remaining Contractual Term, Outstanding	3 years 7 months 13 days
Weighted-Average Remaining Contractual Term, Exercisable	3 years 7 months 13 days
Weighted-Average Remaining Contractual Term, Vested and expected to vest	3 years 7 months 13 days
Aggregate Intrinsic Value, Outstanding	$ 202
Aggregate Intrinsic Value, Exercisable	202
Aggregate Intrinsic Value, Vested and expected to vest	$ 202