Investment in Unconsolidated Joint Ventures (HICO Avalon II, LLC (Details) - HICO Avalon II, LLC $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Schedule of Equity Method Investments [Line Items]
Predevelopment costs, funding percentage	75.00%
Development costs, funding percentage	90.00%
Cash balance of joint venture	$ 114
Hines II
Schedule of Equity Method Investments [Line Items]
Predevelopment costs, funding percentage	25.00%
Development costs, funding percentage	10.00%