Incentive Plans - Additional Information (Detail) (USD $)	3 Months Ended			0 Months Ended	3 Months Ended	0 Months Ended				3 Months Ended	0 Months Ended			3 Months Ended		3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013		Feb. 04, 2014 Performance-Based Restricted Stock Units [Member]	Mar. 31, 2014 Performance-Based Restricted Stock Units [Member]	Feb. 04, 2014 Performance-Based Restricted Stock Units [Member] Minimum [Member]	Feb. 04, 2014 Performance-Based Restricted Stock Units [Member] Maximum [Member]	Feb. 04, 2014 Time Based Restricted Stock Units (RSU) [Member]	Feb. 05, 2014 Time Based Restricted Stock Units (RSU) [Member] Non-employee Director Plan [Member]	Mar. 31, 2014 Time Based Restricted Stock Units (RSU) [Member] Non-employee Director Plan [Member]	Feb. 04, 2014 SAR [Member]	Feb. 04, 2014 Cash-Settled RSU (RSU-C) [Member]	Feb. 04, 2014 Stock Options [Member]	Mar. 31, 2014 Stock Options [Member]	Mar. 31, 2014 Employee Stock Purchase Plan [Member]	Mar. 31, 2014 2012 Long-Term Plan [Member]
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Long term plan expiration year																2022
Maximum number of shares available for issuance															980,000	8,700,000
Maximum number of shares available for issuance, annual rate																1.00%
Granted stock options											183,200		772,900
Granted stock options, exercise price													$ 55.82
Stock-based compensation, fair value assumption model					Monte Carlo valuation model									Black-Scholes valuation model
Granted stock options, valuation per option													$ 12.84
Granted restricted stock				464,300				233,400	43,848			170,900
Granted restricted stock, fair value						$ 33.90	$ 51.30	$ 55.82	$ 55.20
Granted restricted stock, vesting scheme										These shares vest on the third anniversary of the date of grant.
Proceeds from exercise of stock options and employee stock purchase plans	$ 0	$ 1,281,000	[1]
Income tax benefits realized for the tax deductions from option exercises	$ 1,400,000	$ 700,000

[1] Reclassified to conform to current presentation.