Schedule of Information Related to Stock Repurchase Programs (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Jul. 31, 2014	Dec. 31, 2012
Class of Stock [Line Items]
Additional dollars authorized for repurchase	$ 400,000,000			$ 400,000,000
Total number of shares purchased	3,275,837
Total number of shares cancelled	767,704
Aggregate purchase price paid	$ 352,210,000
Aggregate purchase price paid for shares purchased as part of publicly announced program	$ 224,260,000	$ 100,749,000	$ 27,201,000
Stock Repurchase Program
Class of Stock [Line Items]
Total number of shares purchased as part of publicly announced programs	1,874,399
Average price pad per share for shares purchased as part of publicly announced program	$ 119.60
Aggregate purchase price paid for shares purchased as part of publicly announced program	$ 224,172,000
Stock Repurchase Programs Twenty Twelve
Class of Stock [Line Items]
Maximum number of shares that may yet be purchased under the program					767,704
Stock Repurchase Programs Twenty Thirteen
Class of Stock [Line Items]
Total number of shares purchased			427,170
Total number of shares purchased as part of publicly announced programs			0
Aggregate purchase price paid			$ 27,201,000
Maximum number of shares that may yet be purchased under the program			767,704
Stock Repurchase Programs Twenty Fourteen
Class of Stock [Line Items]
Additional dollars authorized for repurchase		$ 400,000,000
Total number of shares purchased		1,029,164
Total number of shares cancelled		767,704
Total number of shares purchased as part of publicly announced programs		548,192
Average price pad per share for shares purchased as part of publicly announced program		$ 105.71
Aggregate purchase price paid		$ 100,749,000
Aggregate purchase price paid for shares purchased as part of publicly announced program		57,950,000
Maximum number of dollars that may yet be purchased under the program		$ 342,050,000
Stock Repurchase Programs Twenty Fifteen
Class of Stock [Line Items]
Total number of shares purchased	1,819,503
Aggregate purchase price paid	$ 224,260,000
Maximum number of dollars that may yet be purchased under the program	$ 175,828,000
Stock Repurchase Programs Twenty Fifteen | Stock Repurchase Program
Class of Stock [Line Items]
Total number of shares purchased as part of publicly announced programs	1,326,207
Average price pad per share for shares purchased as part of publicly announced program	$ 125.34
Aggregate purchase price paid for shares purchased as part of publicly announced program	$ 166,222,000