Stock-Based Compensation Expense - Schedule of Assumptions Used to Value Options Granted (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected life (in years)	5 years	3 years 8 months 12 days	5 years	3 years 8 months 12 days
Risk-free interest rate	1.40%	0.60%
Dividend yield	3.50%	2.70%
Expected volatility	58.90%	63.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Risk-free interest rate			0.80%	0.60%
Dividend yield			2.30%	2.20%
Expected volatility			58.90%	63.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Risk-free interest rate			1.40%	0.80%
Dividend yield			3.50%	2.70%
Expected volatility			59.50%	66.40%