Stockholders' Equity - Schedule of Share Repurchase Authorized by Board of Directors (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
April, 2012 [Member]
Schedule Of Share Repurchase Programs [Line Items]
Share Repurchase Authorization	$ 125,000
Expiration	Dec. 31, 2013
October, 2012 [Member]
Schedule Of Share Repurchase Programs [Line Items]
Share Repurchase Authorization	200,000
Expiration	Dec. 31, 2014
October, 2013 [Member]
Schedule Of Share Repurchase Programs [Line Items]
Share Repurchase Authorization	100,000
Expiration	Dec. 31, 2015
April, 2014 [Member]
Schedule Of Share Repurchase Programs [Line Items]
Share Repurchase Authorization	$ 200,000
Expiration	Dec. 31, 2015