Stock-Based Compensation Plans - Additional Information 2 (Detail) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Mar. 31, 2014	Sep. 30, 2015		Sep. 30, 2014
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense		$ 13,426	$ 13,965		$ 46,328		$ 53,087
Performance Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense		2,400	1,400		$ 6,500		$ 6,100
Units granted	[1]				276,204
Weighted average grant date fair value					$ 56.78	[1]	$ 86.14
Vesting period				3 years	3 years
Equity Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense		5,900	5,800		$ 19,800		$ 21,000
Units granted					586,311		355,000
Weighted average grant date fair value					$ 52.35		$ 84.96
Vesting period					3 years
Restricted Stock Liability Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense		$ 4,400	$ 5,000		$ 16,100		$ 19,800
Units granted					342,495
Weighted average grant date fair value					$ 56.01
Restricted Stock Liability Awards | Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Units granted					295,000		208,000
Weighted average grant date fair value					$ 56.17		$ 87.24
Vesting period					3 years		3 years
Restricted Stock Liability Awards | Non Employee Director
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Units granted					48,000		64,000
Weighted average grant date fair value					$ 55.03		$ 87.97

[1] Amounts granted reflect the number of performance units granted; however, the actual payout of shares will be between zero percent and 150% of the performance units granted depending on the total shareholder return ranking compared to the peer companies at the end of the three-year performance period.