Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

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Amount of paid and unpaid common stock dividends declared with the form of settlement in cash, stock and payment-in-kind (PIK).

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Decrease in noncontrolling interest balance from payment of dividends or other distributions by the non-wholly owned subsidiary or partially owned entity, included in the consolidation of the parent entity, to the noncontrolling interest holders.

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Amount of increase in noncontrolling interest from sale of a portion of the parent's controlling interest.

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Net number of share options (or share units) granted during the period.

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Value, after forfeitures, of stock or other type of equity granted of any equity-based compensation plan other than an employee stock ownership plan (ESOP).

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Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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Amount of stockholders' equity (deficit), net of receivables from officers, directors, owners, and affiliates of the entity, attributable to both the parent and noncontrolling interests. Amount excludes temporary equity. Alternate caption for the concept is permanent equity.

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Amount of stockholders' equity including the portion attributable to noncontrolling interests, after the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

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CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Shares	Additional Paid in Capital	Cumulative Net Income	Cumulative Distributions	Cumulative Other Comprehensive Income (Loss)	Total Equity Attributable to Common Shareholders	Noncontrolling Interest
Balance (in shares) at Dec. 31, 2015		237,471,559
Balance at Dec. 31, 2015	$ 3,359,760	$ 2,375	$ 4,531,703	$ 1,477,590	$ (2,619,371)	$ (32,537)	$ 3,359,760	$ 0
Increase (Decrease) in Shareholders' Equity
Comprehensive income (loss)	208,381			141,295		67,086	208,381
Distributions	(370,489)				(370,489)		(370,489)
Share grants (in shares)		92,150
Share grants	2,205	$ 1	2,204				2,205
Share repurchases (in shares)		(19,230)
Share repurchases	(452)	$ (1)	(451)				(452)
Balance (in shares) at Dec. 31, 2016		237,544,479
Balance at Dec. 31, 2016	3,199,405	$ 2,375	4,533,456	1,618,885	(2,989,860)	34,549	3,199,405	0
Increase (Decrease) in Shareholders' Equity
Comprehensive income (loss)	204,485			147,610		52,682	200,292	4,193
Distributions	(370,608)				(370,608)		(370,608)
Share grants (in shares)		103,100
Share grants	2,130	$ 1	2,129				2,130
Share repurchases (in shares)		(17,170)
Share repurchases	(341)		(341)				(341)
Contributions from noncontrolling interest	255,931		74,072				74,072	181,859
Distributions to noncontrolling interest	$ (13,814)							(13,814)
Balance (in shares) at Dec. 31, 2017	237,630,409	237,630,409
Balance at Dec. 31, 2017	$ 3,277,188	$ 2,376	4,609,316	1,766,495	(3,360,468)	87,231	3,104,950	172,238
Increase (Decrease) in Shareholders' Equity
Cumulative adjustment upon adoption of ASU No. 2016-01	0			87,429		(87,429)
Adjusted balance at beginning of year	3,277,188	$ 2,376	4,609,316	1,853,924	(3,360,468)	(198)	3,104,950	172,238
Comprehensive income (loss)	292,346			286,872		(68)	286,804	5,542
Distributions	(370,746)				(370,746)		(370,746)
Share grants (in shares)		123,800
Share grants	2,515	$ 1	2,514				2,515
Share repurchases (in shares)		(24,309)
Share repurchases	(411)		(411)				(411)
Distributions to noncontrolling interest	$ (21,022)							(21,022)
Balance (in shares) at Dec. 31, 2018	237,729,900	237,729,900
Balance at Dec. 31, 2018	$ 3,179,870	$ 2,377	$ 4,611,419	$ 2,140,796	$ (3,731,214)	$ (266)	$ 3,023,112	$ 156,758