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Variable Interest Entities, Contingent Liabilities and Consolidated Joint Ventures - MCB Real Estate, LLC (Details) - Consolidated JV	9 Months Ended	12 Months Ended
	Sep. 30, 2018 USD ($) item	Dec. 31, 2017 USD ($) item	Jan. 30, 2018
Consolidated VIEs Carrying Amount of Assets and Liabilities
Number of joint ventures with controlling interest	5
Sale of real estate | Retail Property, Fort Bend, Texas | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Consolidated VIEs Carrying Amount of Assets and Liabilities
Ownership interest in consolidated joint venture of the company (as a percent)		85.00%	85.00%
MCB Real Estate LLC And Its Affiliates
Consolidated VIEs Carrying Amount of Assets and Liabilities
Number of joint ventures with controlling interest	4	4
Investment in consolidated joint ventures | $	$ 9,859,000	$ 9,705,000

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- Definition

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- Definition

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- Definition

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