Stock-Based Compensation Plans - Summary of Stock Option Activity Under All Plans (Detail) - Stock Options [Member] - $ / shares shares in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding, beginning of period, Shares	133	148
Granted, Shares	78	28
Exercised, Shares	(33)	(38)
Forfeited, Shares	(19)
Options outstanding, end of period, Shares	159	138
Options exercisable, end of period, Shares	69	77
Options vested and expected to vest, end of period, Shares	155	135
Weighted average fair value of options granted during the period	$ 9.44	$ 19.49
Options outstanding, beginning of period, Exercise Price	49	46
Granted, Exercise Price	58	60
Exercised, Exercise Price	45	48
Forfeited, Exercise Price	57
Options outstanding, end of period, Exercise Price	53	49
Options exercisable, end of period, Exercise Price	49	45
Options vested and expected to vest, end of period, Exercise Price	$ 53	$ 49