Condensed Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended
Sep. 30, 2014	Sep. 30, 2013
Tax benefit related to delivery of Class A Common Stock in connection with share-based incentive compensation	$ 1,409	$ 862

The amount of adjustment to stockholders' equity associated with an employee's income tax withholding obligation as part of a net-share settlement of a share-based award.

No definition available.

Name:	us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration