Stockholders' Equity - Distribution Reinvestment Plan (Narrative) (Details) - USD ($)	3 Months Ended		48 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Oct. 26, 2016	Feb. 09, 2015
Stockholders Equity Note [Line Items]
Gross proceeds raised pursuant to DRP	$ 139,446	$ 7,358
Distribution Reinvestment Plan
Stockholders Equity Note [Line Items]
Percent of estimated value per share	97.00%
Period within which the company expects to establish an estimated value per share following the second anniversary	150 days
Notice period served by board of directors to amend or terminate distribution reinvestment plan	10 days
Gross proceeds raised pursuant to DRP			$ 278,478
Class A common \| Distribution Reinvestment Plan
Stockholders Equity Note [Line Items]
Purchase price (in dollars per share)	$ 9.81		$ 9.81	$ 9.81	$ 9.81
Class T common \| Distribution Reinvestment Plan
Stockholders Equity Note [Line Items]
Purchase price (in dollars per share)	9.27		9.27	9.27	$ 9.27
Class I Common \| Distribution Reinvestment Plan
Stockholders Equity Note [Line Items]
Purchase price (in dollars per share)	$ 9.10		$ 9.10	$ 9.10
Dealer Manager \| Selling Commissions and Fees Related to DRP
Stockholders Equity Note [Line Items]
Selling commissions or dealer manager fees paid	$ 0

NorthStar/RXR New York Metro Real Estate, Inc. 10-Q