Annual report pursuant to Section 13 and 15(d)

Schedule III - Real Estate and Accumulated Depreciation - Change in Balance of Real Estate 2 (Detail)

v3.6.0.2
Schedule III - Real Estate and Accumulated Depreciation - Change in Balance of Real Estate 2 (Detail) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]      
Impairment charge $ 2,016 $ 622 $ 14,238
Roseville, Minnesota [Member]      
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]      
Impairment charge     $ 14,200
Real Estate Held for Sale [Member]      
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]      
Real estate held for sale, gross $ 11,454 $ 1,899