Stock-Based Compensation and Stock Awards - Schedule of Option Activity (Detail) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Number of Options
Options Outstanding, Beginning Balance (in shares)	351,959
Granted (in shares)	0
Exercised (in shares)	(23,247)
Forfeited (in shares)	(48,500)
Options Outstanding, Ending Balance (in shares)	280,212	351,959
Options Exercisable (in shares)	280,212
Weighted Average Price
Weighted Average Price Outstanding, Beginning Balance (in dollars per share)	$ 57.66
Granted (in dollars per share)	0.00
Exercised (in dollars per share)	31.31
Forfeited (in dollars per share)	57.71
Weighted Average Price Outstanding, Ending Balance (in dollars per share)	59.84	$ 57.66
Weighted Average Price Exercisable (in dollars per share)	$ 59.84
Aggregate Intrinsic Value (in millions)
Aggregate intrinsic value Outstanding	$ 0.6
Aggregate intrinsic value Exercisable	$ 0.6
Weighted Average Remaining Contractual Life (in years)
Weighted Average Remaining Contractual Life Outstanding (in years)	2 years 10 months 20 days
Weighted Average Remaining Contractual Life Exercisable (in years)	2 years 10 months 20 days