Share-Based Compensation - Fair Value of Restricted Stock Shares and Units is Market Price of our Common Stock on Date of Grant (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Weighted-Average Grant-Date Fair Value	$ 50.38	$ 35.85	$ 35.91
SARs and Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding at Beginning, Number	3,139
Granted, Number	342
Exercised or converted, Number	(1,705)
Forfeited or expired, Number	(108)
Outstanding at December 31, 2013	1,668
Vested or expected to vest at End, Number	1,631
Exercisable or convertible at End, Number	891
Outstanding at Beginning, Weighted-Average Exercise Price	$ 30.40
Granted, Weighted-Average Exercise Price	$ 50.02
Exercised or converted, Weighted-Average Exercise Price	$ 27.77
Forfeited or expired, Weighted-Average Exercise Price	$ 42.01
Outstanding at End, Weighted-Average Exercise Price	$ 36.37
Vested or expected to vest at End, Weighted-Average Exercise Price	$ 36.22
Exercisable or convertible at End, Weighted-Average Exercise Price	$ 30.48
Outstanding at End, Weighted-Average Remaining Contractual Term	7 years 2 months 12 days
Vested or expected to vest at End, Weighted-Average Remaining Contractual Term	7 years 1 month 6 days
Exercisable or convertible at End, Weighted-Average Remaining Contractual Term	6 years 1 month 6 days
Outstanding at End, Aggregate Intrinsic Value	$ 56,827
Vested or expected to vest at End, Aggregate Intrinsic Value	55,833
Exercisable or convertible at End, Aggregate Intrinsic Value	$ 35,599
Restricted Shares and Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding at Beginning, Number	386
Granted, Number	275
Exercised or converted, Number	(176)
Forfeited or expired, Number	(43)
Outstanding at End, Number	442
Outstanding at Beginning, Weighted-Average Exercise Price	$ 26.67
Granted, Weighted-Average Grant-Date Fair Value	$ 50.38
Exercised or converted, Weighted-Average Grant-Date Fair Value	$ 24.12
Forfeited or expired, Weighted-Average Grant-Date Fair Value	$ 38.19
Outstanding at End, Weighted-Average Exercise Price	$ 41.32