Subsequent Events (Details) (USD $)	0 Months Ended	9 Months Ended	0 Months Ended
	Oct. 14, 2014 Subsequent Event	Sep. 30, 2014 Convertible Notes	Oct. 14, 2014 Convertible Notes Subsequent Event	Oct. 14, 2014 Convertible Notes Subsequent Event	Sep. 30, 2014 Call Options	Oct. 14, 2014 Call Options Subsequent Event	Sep. 30, 2014 Warrants	Sep. 30, 2013 Warrants	Oct. 14, 2014 Warrants Subsequent Event
Subsequent Event [Line Items]
Cash dividend declared per common share	$ 0.35
Cash dividends declared	$ 6,300,000
Conversion rate of common stock shares per $1,000 of principal amount		20.8862	20.9185
Principal amount in conversion feature		$ 1,000		$ 1,000
Conversion price per share of note		$ 47.88		$ 47.80
Exercise price per share of Call Options					$ 47.88	$ 47.80
Exercise price per share of Warrants							60.80	61.14	60.70