Significant Accounting Policies (Treasury Stock) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Treasury Stock
Equity, Class of Treasury Stock [Line Items]
Purchase of treasury shares, shares	111,292	412,473	34,985
Treasury Stock Acquired, Average Cost Per Share	$ 17.97	$ 37.03	$ 30.30
Common Stock
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased	941,250