Summary of Significant Accounting Policies (Details 2)			12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Stock options	Dec. 31, 2011 Stock options
Share-based compensation
Options granted (in shares)			0	252,464
Common Stock Held in Treasury, at Cost
Number of shares of common stock held in treasury	16,005,500	14,677,872