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

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

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Carrying value as of the balance sheet date of dividends declared but unpaid on equity securities issued by the entity and outstanding.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Amount of cash outflow in the form of ordinary dividends to common shareholders of the parent entity.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Topic 230
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Shareholder's Equity - Distribution to Common Shareholders (Details) - USD ($) $ / shares in Units, $ in Thousands					6 Months Ended
	Jul. 19, 2018	May 17, 2018	Feb. 22, 2018	Jan. 19, 2018	Jun. 30, 2018	Jun. 30, 2017
Stockholders' Equity Note [Abstract]
Distribution to common shareholders (in dollars per share)		$ 0.39	$ 0.39
Distribution to common shareholders		$ 92,676	$ 92,674		$ 185,350	$ 185,284
Subsequent Event [Line Items]
Distributions to common shareholders declared (in dollars per share)				$ 0.39
Distribution payable				$ 92,674
Subsequent Event
Subsequent Event [Line Items]
Distributions to common shareholders declared (in dollars per share)	$ 0.39
Distribution payable	$ 92,681