Stockholders' Equity, Stock Repurchase Program and Treasury Stock (Details) - shares	Dec. 31, 2017	Apr. 27, 2005
Stock Repurchase Program [Abstract]
Stock repurchase program, number of shares authorized to be repurchased (in shares)		666,666
Stock repurchase program, remaining number of shares authorized to be repurchased (in shares)	602,467

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