Share-based Compensation - Summary of Company's Stock Option Plan Activity (Detail) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended
	Jun. 30, 2019 USD ($) $ / shares shares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of Shares, Options outstanding, Beginning balance | shares	981
Number of Shares, Granted | shares	100
Number of Shares, Exercised | shares	0
Number of Shares, Forfeited | shares	0
Number of Shares, Expired | shares	0
Number of Shares, Options outstanding, Ending balance | shares	1,081
Number of Shares, Options exercisable | shares	871
Weighted Average Exercise Price Per Share, Options outstanding, Beginning balance | $ / shares	$ 18.69
Weighted Average Exercise Price Per Share, Granted | $ / shares	27.89
Weighted Average Exercise Price Per Share, Exercised | $ / shares	0
Weighted Average Exercise Price Per Share, Forfeited | $ / shares	0
Weighted Average Exercise Price Per Share, Expired | $ / shares	0
Weighted Average Exercise Price Per Share, Options outstanding, Ending balance | $ / shares	19.55
Weighted Average Exercise Price Per Share, Options exercisable | $ / shares	$ 17.83
Weighted Average Remaining Contractual Life (Years), Options outstanding	6 years 4 months 24 days
Weighted Average Remaining Contractual Life (Years), Options exercisable	5 years 9 months 18 days
Aggregate Intrinsic Value, Options outstanding | $	$ 7,936
Aggregate Intrinsic Value, Options exercisable | $	$ 7,715