Fair Value Measurements (Fair Value Measurements on a Nonrecurring Basis) (Details) - Real Estate - Fair Value, Measurements, Nonrecurring $ in Thousands	Dec. 31, 2018 USD ($)
Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis
Real estate assets	$ 14,971
Level 1
Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis
Real estate assets	0
Level 2
Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis
Real estate assets	0
Level 3
Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis
Real estate assets	$ 14,971