Share Based Compensation (Schedule of Weighted-Average Assumptions) (Detail)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	1.25%
Dividend yield
Expected volatility	37.00%
Expected life (in years)	7 months 17 days
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	0.59%	1.47%	1.93%
Dividend yield
Expected volatility	36.49%	37.83%	44.53%
Expected life (in years)	4 years	4 years 11 days	42 months 9 days