Weighted-Average Assumptions Used to Determine the Fair Value of the SARs Grants on the Date of the Grant Using the Black-Scholes-Merton Valuation Model (Detail) (Stock Appreciation Rights)	12 Months Ended
	Dec. 31, 2011 Year		Dec. 31, 2010 Year		Dec. 31, 2009 Year
Stock Appreciation Rights
Share based Compensation Arrangement by Share based Payment Award, Fair Value Assumptions, Method Used [Line Items]
Expected dividend yield	0.00%	[1]	0.00%	[1]	0.00%	[1]
Expected stock price volatility	38.00%	[2]	40.00%	[2]	50.00%	[2]
Risk-free interest rate	2.20%	[3]	2.40%	[3]	2.30%	[3]
Expected life in years	4.75	[4]	4.75	[4]	4.80	[4]

[1] The dividend yield assumption is based on both the history and expectation of the Company's dividend payouts. Historically the Company has not paid cash dividends on its Common Stock.

[2] The determination of expected stock price volatility was based on both historical Common Stock prices and implied volatility from publicly traded options in Common Stock.

[3] The risk-free interest rate is based on the yield of a U.S. Treasury security with a maturity similar to the expected life of the award.

[4] The expected life in years represents a weighted-average estimate of the period of time the SARs are expected to be outstanding (that is, the period of time between the service inception date and the expected exercise date). The expected life is based on the "simplified" calculation permitted by SAB No. 107. Under the simplified method, the expected life in years is determined by taking the average of the vesting period plus the original contractual term and dividing by two. The Company continues to use the simplified method for SARs since it does not have the necessary actual historical exercise and forfeiture data, as permitted by SAB No. 110.