Information of Option Outstanding and Exercisable (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding and Exercisable, Number	632	2,091	4,450	5,316
Options Outstanding and Exercisable, Weighted-Average Remaining Contractual Life	11 months 19 days
Options Outstanding and Exercisable, Weighted-Average Exercise Price	$ 27.41	$ 24.80	$ 21.85	$ 22.04
Options Outstanding and Exercisable, Aggregate Intrinsic Value	$ 9,217
$23.49 to $26.12
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Prices, Lower	$ 23.49
Range of Exercise Prices, Upper	$ 26.12
Options Outstanding and Exercisable, Number	163
Options Outstanding and Exercisable, Weighted-Average Remaining Contractual Life	1 year 1 month 2 days
Options Outstanding and Exercisable, Weighted-Average Exercise Price	$ 25.82
Options Outstanding and Exercisable, Aggregate Intrinsic Value	2,639
$26.13 to $26.13
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Prices, Lower	$ 26.13
Range of Exercise Prices, Upper	$ 26.13
Options Outstanding and Exercisable, Number	11
Options Outstanding and Exercisable, Weighted-Average Remaining Contractual Life	3 months 18 days
Options Outstanding and Exercisable, Weighted-Average Exercise Price	$ 26.13
Options Outstanding and Exercisable, Aggregate Intrinsic Value	173
$26.56 to $26.56
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Prices, Lower	$ 26.56
Range of Exercise Prices, Upper	$ 26.56
Options Outstanding and Exercisable, Number	239
Options Outstanding and Exercisable, Weighted-Average Remaining Contractual Life	9 months 26 days
Options Outstanding and Exercisable, Weighted-Average Exercise Price	$ 26.56
Options Outstanding and Exercisable, Aggregate Intrinsic Value	3,688
$27.36 to $33.89
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Prices, Lower	$ 27.36
Range of Exercise Prices, Upper	$ 33.89
Options Outstanding and Exercisable, Number	219
Options Outstanding and Exercisable, Weighted-Average Remaining Contractual Life	1 year 22 days
Options Outstanding and Exercisable, Weighted-Average Exercise Price	$ 29.58
Options Outstanding and Exercisable, Aggregate Intrinsic Value	$ 2,717