Share Based Compensation - Total Compensation Cost Charged, Weighted Average Assumptions (Parenthetical) (Details) - shares	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share Based Compensation [Abstract]
Stock options granted, shares	0	176,000	186,000

Gross number of share options (or share units) granted during the period.

No definition available.

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration