Shareholder-Designated Contribution Plan (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013 Contribution
Shareholder-Designated Contribution Plan [Abstract]
Shareholder-designated contribution	2
Shareholder-designated contribution, diluted per share (in dollars per share)	$ 0.24
Initial contribution per registered share to Shareholder-designated charitable contribution program (in dollars per share)	$ 0.25
Expected expense related to Shareholder-designated charitable contribution program	$ 10.6