Stockholders' Equity - Additional Information (Details) shares in Millions	Dec. 31, 2017 shares
Equity [Abstract]
Shares remaining under existing repurchase program	2.3

The remaining number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

No definition available.

Name:	us-gaap_StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant