Earnings Per Share (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Weighted-average shares:
Common shares outstanding	80,566,400	80,389,996	80,565,754	80,389,131
Restricted common shares	645,427	600,581	604,179	581,932
Total Weighted Average Shares	81,211,827	80,990,577	81,169,933	80,971,063
Percentage of weighted-average shares:
Common shares outstanding	99.21%	99.26%	99.26%	99.28%
Restricted common shares	0.79%	0.74%	0.74%	0.72%
Total	100.00%	100.00%	100.00%	100.00%