Stock-Based Compensation - Restricted Stock Activity and Incentive Stock Awards Activity (Detail)	6 Months Ended
	Jun. 30, 2016 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Outstanding, beginning of period (in dollars per share) | $ / shares	$ 65.89
Granted (in dollars per share) | $ / shares	62.20
Vested (in dollars per share) | $ / shares	52.12
Adjustment for incentive stock awards expected to vest (in dollars per share) | $ / shares	73.28
Canceled (in dollars per share) | $ / shares	70.48
Outstanding, end of period (in dollars per share) | $ / shares	$ 70.85
Restricted Stock and Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding, beginning of period (in shares)	356,885
Granted (in shares)	142,891
Vested (in shares)	(148,753)
Adjustment for incentive stock awards expected to vest (in shares)	0
Canceled (in shares)	(7,519)
Outstanding, end of period (in shares)	343,504
Incentive Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding, beginning of period (in shares)	541,638
Granted (in shares)	167,850
Vested (in shares)	(236,591)
Adjustment for incentive stock awards expected to vest (in shares)	(27,784)
Canceled (in shares)	(5,283)
Outstanding, end of period (in shares)	439,830