Stock-Based Compensation - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013 Plans	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock based compensation plan	1
Stock compensation expense	$ 3,811,000	$ 3,469,000	$ 3,146,000
Stock Appreciation Rights [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum contractual term of Stock Appreciation Rights	10 years
Unrecognized compensation cost related to unvested awards	1,500,000
Recognized period for of cost of unvested awards	1 year 8 months 12 days
Weighted-average fair value of grants	$ 43.89	$ 25.75	$ 25.76
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense	2,500,000	2,000,000	1,600,000
Unrecognized compensation cost related to unvested awards	3,600,000
Recognized period for of cost of unvested awards	1 year 10 months 24 days
Restricted Stock, Granted	47,015	156,927	67,945
Weighted-Average Grant Price Per Share, Granted	$ 44.42	$ 27.18	$ 25.86
Total fair value of restricted shares vested	3,100,000	2,500,000	4,100,000
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total aggregate number of shares of common stock that may be issued	300,000
Stock compensation expense	98,700	65,300	86,300
Percentage of market price on lesser of either first day of calendar quarter or last day of calendar quarter for purchase price	85.00%
Approximate number of shares employees purchased under the Employee Stock Purchase Plan	200,000
Percentage of gross compensation eligible employees may elect to participate in the plan	15.00%
2005 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total aggregate number of shares of common stock that may be issued	3,150,000
Stock compensation expense	$ 3,800,000	$ 3,500,000	$ 3,100,000