Share-Based Compensation (Summary of Stock Option Activity) (Detail) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2016 USD ($) $ / shares shares
Stock option
Balance at December 31, 2015 | shares	132
Exercised during 2016 | shares	0
Balance at September 30, 2016 | shares	132
Vested and expected to vest at September 30, 2016 | shares	132
Exercisable at September 30, 2016 | shares	66
Stock option, weighted-average exercise price
Beginning Balance, Weighted-average exercise price | $ / shares	$ 27.66
Exercised, Weighted-average exercise price | $ / shares	0
Ending Balance, Weighted-average exercise price | $ / shares	27.66
Vested and expected to vest at September 30, 2016, Weighted-average exercise price | $ / shares	27.66
Exercisable at September 30, 2016, Weighted-average exercise price | $ / shares	$ 27.66
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures
Ending Balance, Weighted-average remaining contractual term, years	7 years 2 months 12 days
Vested and expected to vest at September 30, 2016, Weighted-average remaining contractual term, years	7 years 2 months 12 days
Exercisable at September 30, 2016, Weighted-average remaining contractual term, years	7 years 2 months 12 days
Ending Balance, Aggregate intrinsic value | $	$ 1,391
Vested and expected to vest at September 30, 2016, Aggregate intrinsic value | $	1,391
Exercisable at September 30, 2016, Aggregate intrinsic value | $	$ 696