Shareholders' Equity, Noncontrolling Interests and Other Comprehensive Income - Common Shares, Share Repurchases and Dividends and Distributions (Details) - USD ($)					1 Months Ended	3 Months Ended								12 Months Ended
	Nov. 08, 2016	Nov. 07, 2016	Nov. 10, 2015	Dec. 05, 2014	Jul. 31, 2016	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2001
Class of Stock [Line Items]
Authorized amount						$ 20,000,000.0								$ 20,000,000.0
Treasury stock, acquired (in shares)														0	0		2,100,000
Remaining authorized repurchase amount						$ 7,500,000								$ 7,500,000
Distributions declared (in dollars per share)						$ 0.41	$ 0.25	$ 0.25	$ 0.25	$ 0.50	$ 0.24	$ 0.24	$ 0.24	$ 1.16	$ 1.22	$ 1.23
ATM Equity Program [Member]
Class of Stock [Line Items]
Proceeds from issuance of common stock															$ 64,400,000	$ 126,800,000
Stock, shares authorized not issued																200,000,000.0
Public Offering [Member]
Class of Stock [Line Items]
Proceeds from issuance of common stock																$ 230,700,000
Restricted Stock [Member]
Class of Stock [Line Items]
Restricted stock, shares canceled for tax withholding for share based compensation (in shares)														3,152	2,481
LTIP Units and Restricted Stock [Member]
Class of Stock [Line Items]
Unit based compensation														$ 10,900,000	$ 6,800,000
Common Shares
Class of Stock [Line Items]
Issuance of Common Shares, net of issuance costs (in Shares)														4,830,000	1,600,000
Stock issued during period														$ 175,200,000
Proceeds from issuance of common stock														$ 172,100,000
Common Shares | Forward Sale and Underwritten Public Offering [Member]
Class of Stock [Line Items]
Issuance of Common Shares, net of issuance costs (in Shares)														3,600,000
Stock issued during period														$ 126,800,000
Proceeds from issuance of common stock														$ 124,500,000
Common Shares | ATM Equity Program [Member]
Class of Stock [Line Items]
Issuance of Common Shares, net of issuance costs (in Shares)														4,500,000		5,000,000
Stock issued during period														$ 157,600,000
Proceeds from issuance of common stock														155,700,000
Additional maximum gross proceeds amount					$ 250,000,000									250,000,000
Sale of Stock, remaining value under program														$ 218,000,000
Regular Quarterly Cash Dividend [Member]
Class of Stock [Line Items]
Cash dividends declared, period increase (in dollars per share)	$ 0.01
Distributions declared (in dollars per share)	0.26	$ 0.25
Special Cash Dividend [Member]
Class of Stock [Line Items]
Distributions declared (in dollars per share)	0.15		$ 0.25	$ 0.30
Cash dividends paid (in dollars per share)	$ 0.15
Common Shares
Class of Stock [Line Items]
Issuance of Common Shares, net of issuance costs (in Shares)														12,961,000	1,973,000	12,237,000
Common Shares | ATM Equity Program [Member]
Class of Stock [Line Items]
Issuance of Common Shares, net of issuance costs (in Shares)															2,000,000
Common Shares | Public Offering [Member]
Class of Stock [Line Items]
Issuance of Common Shares, net of issuance costs (in Shares)																7,600,000