Real Estate Investments - Additional Information (Details) $ in Thousands	Dec. 31, 2016 USD ($) item
Clubhouse
REAL ESTATE INVESTMENTS
Construction contract amount	$ 1,232
Construction contract, amount completed to date	1,120
Construction contract, retainage amount included in payables	56
Townhomes
REAL ESTATE INVESTMENTS
Construction contract amount	7,829
Construction contract, amount completed to date	4,647
Construction contract, retainage amount included in payables	$ 232
Multifamily | Bismarck, North Dakota
REAL ESTATE INVESTMENTS
Number of two-story townhomes under construction | item	6
Number of apartment buildings under construction | item	6
Estimated cost of project	$ 9,061