Earnings per Share (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Restricted Shares [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Incremental common shares attributable to share-based payment arrangements	231,434	289,120	176,667	164,163
Stock Options [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Incremental common shares attributable to share-based payment arrangements	169,241	174,101	184,065	220,937