Stock Incentive Plans - Summary of Employee Restricted Common Stock Grant Awards (Details) - Restricted Common Stock - shares	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted during the year (in shares)	685,872
Unvested (in shares)	639,329	374,817
Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted during the year (in shares)	663,960	401,520	482,001
Unvested (in shares)	425,160	118,220	28,387
Employees \| December 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested (in shares)	212,580	118,220	28,387
Employees \| December 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested (in shares)	212,580	0	0

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).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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