Debt (Schedule of Construction Financing) (Details) - Union Square Construction Financing [Member] $ in Thousands		9 Months Ended	12 Months Ended
		Sep. 30, 2018 USD ($) item	Dec. 31, 2017	Dec. 29, 2016 USD ($)
Debt Instrument [Line Items]
Facility Limit		$ 57,500
Advanced-to-Date		25,852
Remaining Facility		$ 31,648
Maturity date		Dec. 29, 2019	Dec. 29, 2019
Number of extension options | item		2
Extension period		1 year
Senior Loan [Member]
Debt Instrument [Line Items]
Advanced-to-Date		$ 7,500
Tammany Mezz Investor, LLC [Member] | Mezzanine Loan [Member]
Debt Instrument [Line Items]
Facility Limit		7,500
Advanced-to-Date		$ 7,500
Interest rate	[1]	10.50%
Spread over LIBOR	[1]	10.00%
Maturity date	[2]	Dec. 29, 2019
Bank Of The Ozarks [Member]
Debt Instrument [Line Items]
Facility Limit				$ 8,000
Advanced-to-Date				$ 8,000
Bank Of The Ozarks [Member] | Senior Loan [Member]
Debt Instrument [Line Items]
Facility Limit		$ 50,000
Advanced-to-Date		18,352
Remaining Facility		$ 31,648
Interest rate	[1]	4.75%
Spread over LIBOR	[1]	4.25%
Maturity date	[2]	Dec. 29, 2019
Maximum [Member] | New York State [Member]
Debt Instrument [Line Items]
Interest rate		16.00%

[1] Not to exceed the New York State maximum lawful borrowing rate, which typically is 16%.

[2] Allowable for up to two (2) extension request options, one (1) year for each extension request.