Quarterly report pursuant to Section 13 or 15(d)

Summary of Potential Number of Shares Vesting under Restricted Stock Unit Awards (Detail)

v3.8.0.1
Summary of Potential Number of Shares Vesting under Restricted Stock Unit Awards (Detail)
$ in Thousands
3 Months Ended
Mar. 31, 2018
USD ($)
shares
Disclosure Of Restricted Stock Unit [Abstract]  
Number of shares vesting at IRR of at least 7% | shares 74,867
Number of shares vesting at IRR of at least 9.5% | shares 149,735
Number of shares vesting at IRR of at least 13% | shares 224,602
Value at grant at IRR of at least 7% | $ $ 2,922
Value at grant at IRR of at least 9.5% | $ 5,844
Value at grant at IRR of at least 13% | $ $ 8,766