Stock-Based Compensation - Summary of Stock Appreciation Rights (Detail)
$ / shares in Units, $ in Thousands |
12 Months Ended |
|
Dec. 31, 2015
USD ($)
$ / shares
shares
|
|---|
| Time-Based Stock Appreciation Rights [Member] |
|
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |
|
| Number of Shares, Outstanding, Beginning Balance | shares |
3,853,367
|
| Number of Shares, Granted | shares |
483,000
|
| Number of Shares, Exercised | shares |
(150,050)
|
| Number of Shares, Forfeited or expired | shares |
(77,133)
|
| Number of Shares, Outstanding, Ending Balance | shares |
4,109,184
|
| Number of Shares, Exercisable | shares |
3,456,039
|
| Number of Shares, Vested and expected to vest | shares |
4,109,184
|
| Weighted-Average Exercise Price, Outstanding, Beginning Balance | $ / shares |
$ 4.53
|
| Weighted-Average Exercise Price, Granted | $ / shares |
6.07
|
| Weighted-Average Exercise Price, Exercised | $ / shares |
4.03
|
| Weighted-Average Exercise Price, Forfeited or expired | $ / shares |
5.39
|
| Weighted-Average Exercise Price, Outstanding, Ending Balance | $ / shares |
5.22
|
| Weighted-Average Exercise Price, Exercisable | $ / shares |
5.16
|
| Weighted-Average Exercise Price, Vested and expected to vest | $ / shares |
$ 5.22
|
| Weighted-Average Remaining Contractual Term, Outstanding |
5 years 7 months 28 days
|
| Weighted-Average Remaining Contractual Term, Exercisable |
4 years 11 months 19 days
|
| Weighted-Average Remaining Contractual Term, Vested and expected to vest |
5 years 7 months 28 days
|
| Aggregate Intrinsic Value, Outstanding, Ending balance | $ |
$ 10,610
|
| Aggregate Intrinsic Value, Exercisable | $ |
10,197
|
| Aggregate Intrinsic Value, Vested and expected to vest | $ |
$ 10,610
|
| Performance-Based Stock Appreciation Rights [Member] |
|
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |
|
| Number of Shares, Outstanding, Beginning Balance | shares |
786,034
|
| Number of Shares, Granted | shares |
8,000
|
| Number of Shares, Exercised | shares |
(15,100)
|
| Number of Shares, Forfeited or expired | shares |
(160)
|
| Number of Shares, Outstanding, Ending Balance | shares |
778,774
|
| Number of Shares, Exercisable | shares |
774,774
|
| Number of Shares, Vested and expected to vest | shares |
778,774
|
| Weighted-Average Exercise Price, Outstanding, Beginning Balance | $ / shares |
$ 5.51
|
| Weighted-Average Exercise Price, Granted | $ / shares |
5.65
|
| Weighted-Average Exercise Price, Exercised | $ / shares |
2.92
|
| Weighted-Average Exercise Price, Forfeited or expired | $ / shares |
5.65
|
| Weighted-Average Exercise Price, Outstanding, Ending Balance | $ / shares |
6.33
|
| Weighted-Average Exercise Price, Exercisable | $ / shares |
6.33
|
| Weighted-Average Exercise Price, Vested and expected to vest | $ / shares |
$ 6.33
|
| Weighted-Average Remaining Contractual Term, Outstanding |
4 years 4 months 17 days
|
| Weighted-Average Remaining Contractual Term, Exercisable |
4 years 4 months 6 days
|
| Weighted-Average Remaining Contractual Term, Vested and expected to vest |
4 years 4 months 17 days
|
| Aggregate Intrinsic Value, Outstanding, Ending balance | $ |
$ 2,177
|
| Aggregate Intrinsic Value, Exercisable | $ |
2,170
|
| Aggregate Intrinsic Value, Vested and expected to vest | $ |
$ 2,177
|