Stock-based Compensation - Summary of SARs Activity (Detail) - SARs [Member] $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares, Beginning Balance | shares	616,650
Granted, Shares | shares	171,131
Exercised, Shares | shares	(117,942)
Forfeited, Shares | shares	(30,693)
Shares, Ending Balance | shares	639,146
Weighted Average Exercise Price, Beginning Balance | $ / shares	$ 55.23
Granted, Weighted Average Exercise Price | $ / shares	73.11
Exercised, Weighted Average Exercise Price | $ / shares	49.68
Forfeited, Weighted Average Exercise Price | $ / shares	63.66
Weighted Average Exercise Price, Ending balance | $ / shares	$ 60.64
Weighted Average Remaining Contractual Term, Ending balance	7 years 1 month 6 days
Aggregate Intrinsic Value, Ending balance | $	$ 8,430