Fair Value Measurements (Fair Value Measurements on a Nonrecurring Basis) (Details) - Real estate assets - Nonrecurring $ in Thousands	Dec. 31, 2020 USD ($)
Financial Assets and Liabilities Measured at Fair Value on a Non-Recurring Basis
Real estate assets	$ 191,116
Level 1
Financial Assets and Liabilities Measured at Fair Value on a Non-Recurring Basis
Real estate assets	0
Level 2
Financial Assets and Liabilities Measured at Fair Value on a Non-Recurring Basis
Real estate assets	0
Level 3
Financial Assets and Liabilities Measured at Fair Value on a Non-Recurring Basis
Real estate assets	$ 191,116