Aggregate dividends paid during the period for each share of common stock outstanding.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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Aggregate dividends declared during the period for each share of common stock outstanding.

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Amount of paid and unpaid preferred stock dividends declared with the form of settlement in cash.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 405
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6957935&loc=d3e64057-112817

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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Shareholders' Equity - Distributions (Details) - USD ($) $ / shares in Units, $ in Thousands	Oct. 12, 2017	Aug. 17, 2017	May 18, 2017	Feb. 21, 2017	Jan. 17, 2017
Distributions
Common stock, quarterly per share distribution (in dollars per share)		$ 0.52	$ 0.52	$ 0.51
Common stock dividend		$ 85,427	$ 85,419	$ 83,777
Series D preferred shareholders'
Distributions
Preferred stock, per share distribution (in dollars per share)					$ 0.4453
Preferred stock dividend					$ 5,166
Subsequent event
Distributions
Common stock dividend	$ 85,462
Quarterly distribution declared (in dollars per share)	$ 0.52