Treasury Stock - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	1 Months Ended	9 Months Ended
	Apr. 25, 2013	Sep. 30, 2013
Stockholders Equity [Line Items]
Additional amount authorized by Board of Directors	$ 25,000
Authorization amount for repurchase of common stock	75,000
Expiration date on repurchase authorizations		Sep. 30, 2014
Common stock acquired, shares		333
Aggregate cost shares of common stock		8,036
Since Approval of Share Repurchase Plan [Member]
Stockholders Equity [Line Items]
Common stock acquired, shares		2,743
Aggregate cost shares of common stock		47,173
Remaining authorized repurchase amount		$ 27,827