Stock-Based Compensation Plans - Additional Information 2 (Detail) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended			6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Mar. 31, 2014	Jun. 30, 2015		Jun. 30, 2014
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense		$ 18,411	$ 24,985		$ 32,902		$ 39,122
Performance Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense					$ 4,100		$ 4,700
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					$ 14,000		$ 14,700
Units granted					583,011		355,000
Weighted average grant date fair value					$ 52.45		$ 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					$ 11,700		$ 15,200
Units granted					332,588
Weighted average grant date fair value					$ 56.45
Restricted Stock Liability Awards | Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Units granted					294,000		207,000
Weighted average grant date fair value					$ 56.20		$ 87.27
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					39,000		61,000
Weighted average grant date fair value					$ 58.35		$ 88.47

[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.