Earnings Per Common Share - Antidilutive (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Issued (in shares)	2,015	3,766	3,864	3,766
Converted (in shares)	1,917	8,509	8,630	8,509
Operating Partnership Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Issued (in shares)	1,917	1,917	1,917	1,917
Converted (in shares)	1,917	1,917	1,917	1,917
Series D Preferred Shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Issued (in shares)	0	1,849	1,849	1,849
Converted (in shares)	0	6,592	6,713	6,592
Performance Share Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Issued (in shares)	98	0	98	0
Converted (in shares)	0	0	0	0