Commitments and Contingencies (Details) $ in Thousands								3 Months Ended		25 Months Ended
	Feb. 28, 2018 USD ($) ft²	Oct. 18, 2017 USD ($) ft²	Oct. 04, 2017 USD ($) a ft² building	Sep. 05, 2017 USD ($)	May 05, 2017 USD ($) a	Mar. 29, 2017 ft²	Jan. 25, 2016 USD ($) a	Feb. 28, 2018 USD ($)	Feb. 28, 2017 USD ($)	Feb. 28, 2018 USD ($)	Jun. 01, 2018 ft²	Mar. 29, 2018 ft²	Mar. 23, 2018 USD ($) a	Jan. 11, 2018 USD ($) a
Purchase and sale obligations
Number of Buildings | building			2
Rental revenue								$ 8,180	$ 6,979
Subsequent events
Purchase and sale obligations
Number of acres | ft²												234,000
Tenant bankruptcy
Purchase and sale obligations
Area Of Building | ft²						100,000
Area Of Leased Space | ft²											52,000
Lease Termination Fee				$ 243
Rental revenue								249
Agreement to sell
Purchase and sale obligations
Purchase obligations							$ 7,700
Number of acres | a							280
Agreement Term of Extension					3 years		3 years
Purchase Option Term							3 months
Agreement Extension Fee										$ 260
Additional option fee					$ 35
Purchase agreement
Purchase and sale obligations
Purchase obligations			$ 2,600											$ 3,600
Area Of Building | ft²			283,000
Number of acres | a			22											14
Lease and development agreement
Purchase and sale obligations
Purchase obligations		$ 15,000
Agreement Term of Extension		5 years
Lease term		12 years 6 months
Lease and development agreement | Expansion option
Purchase and sale obligations
Area Of Building | ft²		54,000
Lease term		10 years
Obligations For Investments In Real Estate Assets
Purchase and sale obligations
Purchase obligations	$ 19,301							$ 19,301		$ 19,301
Area Of Building | ft²	134,000
Southwick Ma Site [Member] | Subsequent events
Purchase and sale obligations
Number of acres to be sold | a													49
Sale price													$ 850
East Granby And Windsor Ct Site [Member] | Agreement to sell
Purchase and sale obligations
Purchase Option Term					3 months
Number of acres to be sold | a					288
Sale price					$ 7,800