Stock Options and Restricted Stock - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011	Dec. 31, 2010
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock based compensation expense	$ 6,500,000		$ 8,400,000	$ 4,800,000
Excess tax benefits included in cash provided by financing activities	5,967,000		1,264,000	321,000
Aggregate number of shares of common stock issued or transferred under the incentive stock awards plan	14,492,585
Unexercised options lapse period	10 years
Stock options granted				347,000
Weighted average fair value of options granted				$ 10.31
Risk-free interest rate				3.59%
Dividend yield				0.25%
Volatility factor of the expected market price				0.41
Weighted average assumptions of forfeiture rate				3.89%
Weighted average expected life of the option				9 years
Aggregate Intrinsic value of options exercised	20,033,000		5,500,000	848,000
Fair value of options vested	2,200,000		2,700,000	3,200,000
Income tax expense benefit resulting from stock options exercised	8,400,000		2,100,000	1,400,000
Separation costs	10,400,000		3,500,000
Separation costs related to share based compensation	1,700,000
Vested	25,000		50,000
Incremental compensation cost resulting from modification	1,200,000		1,300,000
Stock options
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Unrecognized compensation expense related to non-vested award	12,200,000
Unrecognized compensation expense related to non-vested award, recognition period	2 years 6 months
Stock options | Minimum
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Vesting period	2 years
Stock options | Maximum
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Vesting period	5 years
Restricted Stock
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock granted	368,000	[1]	266,000	300,000
Weighted average grant date fair value	$ 26.08	[1]	$ 23.57	$ 16.20
Total fair value of shares vesting	$ 4,400,000		$ 5,700,000	$ 1,500,000
Vested	75,000
Restricted Stock | Minimum
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Vesting period	2 years
Restricted Stock | Maximum
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Vesting period	5 years
Restricted stock awards
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Vested	75,000		150,000

[1] Includes 250,000 RSUs granted to certain executive officers that will be eligible to vest on March 31, 2015 assuming certain performance conditions are achieved over three annual performance periods. The Company recognizes compensation cost for its performance-based RSUs over the vesting period based on the probability that the performance condition will be satisfied.