Shareholders' Equity - 2012 Equity Incentive Plan Narrative (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Stock options and Restricted stock units
Class of Stock [Line Items]
Allocated share-based compensation expense	$ 0.9	$ 0.9
Stock options and Restricted stock units \| 2012 Equity Incentive Plan
Class of Stock [Line Items]
Vesting period for stock options and restricted stock units	4 years
Expiration period for stock options and restricted stock units	10 years
Stock options \| 2012 Equity Incentive Plan
Class of Stock [Line Items]
Granted (in shares)	385,200	688,000
Restricted stock units \| 2012 Equity Incentive Plan
Class of Stock [Line Items]
Restricted stock unit grants in period (in shares)	174,000	74,100
General and Administrative Expense [Member]
Class of Stock [Line Items]
Allocated share-based compensation expense	$ 0.5	$ 0.5
Property Management Expense [Member]
Class of Stock [Line Items]
Allocated share-based compensation expense	$ 0.4	$ 0.4

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.F)
-URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
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-Paragraph 2
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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
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Gross number of share options (or share units) granted during the period.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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