Subsequent Events (Details)						5 Months Ended	6 Months Ended
	Aug. 12, 2015 USD ($) shares	Jul. 29, 2015 USD ($) ft²	Jul. 22, 2015 USD ($) ft²	Jul. 01, 2015 USD ($) ft²	Jun. 24, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) shares	Aug. 10, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 12, 2014 USD ($)	Sep. 23, 2014 USD ($)
Subsequent Event [Line Items]
Investment by private investment program											$ 2,000,000.0
Proceeds from borrowings - Credit Facility						$ 0	$ 195,900,000
Proceeds from Issuance of Preferred Limited Partners Units					$ 150,000,000		32,560,000
Subsequent Event
Subsequent Event [Line Items]
Proceeds from Issuance of Preferred Limited Partners Units			$ 10,800,000	$ 2,600,000
Revolving Credit Facility
Subsequent Event [Line Items]
Revolving credit facility current borrowing capacity										$ 250,000,000.0
Revolving credit facility, maximum borrowing capacity										$ 1,250,000,000.00
Revolving Credit Facility | Subsequent Event
Subsequent Event [Line Items]
Proceeds from borrowings - Credit Facility	$ 241,200,000	$ 21,600,000	$ 16,800,000	$ 6,900,000
Revolving credit facility, maximum borrowing capacity								$ 410,000,000
Morpho Detection Property | Subsequent Event
Subsequent Event [Line Items]
Net rentable area | ft²				64,200
Lease term				11 years 10 months 24 days
Purchase price				$ 11,500,000
FedEx Freight Property | Subsequent Event
Subsequent Event [Line Items]
Net rentable area | ft²			160,400
Lease term			8 years 6 months
Purchase price			$ 28,000,000
Aetna Property | Subsequent Event
Subsequent Event [Line Items]
Net rentable area | ft²		100,300
Lease term		10 years
Purchase price		$ 21,700,000
Class A
Subsequent Event [Line Items]
Investment by private investment program							$ 144,819		$ 11,335
Class A | Subsequent Event
Subsequent Event [Line Items]
Common Stock, Shares Subscribed but Unissued | shares	17,046,997
Common Stock, Value, Subscriptions	$ 169,539,971
Class A | Distribution Reinvestment Plan | Subsequent Event
Subsequent Event [Line Items]
Investment by private investment program	$ 1,640,790
Common stock, number of shares issued (in shares) | shares	172,715
Series A Cumulative Redeemable Preferred Units
Subsequent Event [Line Items]
Preferred Units, Outstanding | shares							3,256,000
Series A Cumulative Redeemable Preferred Units | Subsequent Event
Subsequent Event [Line Items]
Preferred Units, Outstanding | shares	2,171,000