Stock Based Compensation (Details) (USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Stock-based compensation
Number of stock-based employee compensation plans	4
Number of executive stock award plans	3
Outstanding stock options (in shares)	0	0
Total unrecognized compensation cost related to non-vested share-based compensation arrangements	$ 6.94
Weighted-average period over which unrecognized compensation cost is expected to be recognized	3 years 2 months 18 days
Stock options
Stock-based compensation
Total fair value of options vested and expensed	$ 0	$ 0
Outstanding stock options (in shares)	0	0
Stock options exercised (in shares)		7,500
Weighted average price of stock options exercised (in dollars per share)		$ 12.04