Share-Based Compensation Expense (Schedule of stock options exercisable) (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Number of shares, Exercisable Stock Options Outstanding	511
Weighted Average Exercise Price, Exercisable	$ 13.79
$0.00 - $9.99 [Member]
Number of shares, Exercisable Stock Options Outstanding	32
Weighted Average Exercise Price, Exercisable	$ 9.55
Exercisable Stock Options Weighted Average Remaining Life	4 years 3 months 18 days
$10.00-$14.99 [Member]
Number of shares, Exercisable Stock Options Outstanding	342
Weighted Average Exercise Price, Exercisable	$ 12.13
Exercisable Stock Options Weighted Average Remaining Life	2 years 8 months 12 days
$15.00-$19.99 [Member]
Number of shares, Exercisable Stock Options Outstanding	128
Weighted Average Exercise Price, Exercisable	$ 18.81
Exercisable Stock Options Weighted Average Remaining Life	6 months
$20.00 and above [Member]
Number of shares, Exercisable Stock Options Outstanding	9
Weighted Average Exercise Price, Exercisable	$ 20.56
Exercisable Stock Options Weighted Average Remaining Life	1 year 2 months 12 days