Summary of Significant Accounting Policies and Procedures and Recent Accounting Pronouncements - Net Income Per Common Share (Details) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net income per common share
Weighted average shares used for the basic net income per share computation	273,465,680	255,066,500	235,767,932
Incremental shares from share-based compensation	154,050	240,728	123,436
Weighted average shares used for diluted net income per share computation	273,936,752	255,624,250	236,208,390
Unvested Shares
Net income per common share
Unvested shares from share-based compensation that were anti-dilutive	32,205	475	106,103
Convertible Partnership Units
Net income per common share
Weighted average partnership common units convertible to common shares that were dilutive	317,022	317,022	317,022
Unvested shares from share-based compensation that were anti-dilutive	88,182	198,429	417,060