Shareholder's Equity (Narrative) (Details) $ in Millions	Dec. 31, 2017 USD ($)
Shareholders' Equity [Abstract]
Amount of outstanding common stock available to be repurchased	$ 15.0
Total remaining authorization under the repurchase program	$ 14.7

Amount remaining of a stock repurchase plan authorized.

No definition available.

Name:	us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant