Fair Value Measurements - Recurring and Nonrecurring Basis (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of Real Estate	$ (31,041)	$ 0	$ (1,700)
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	42,760
Impairment of Real Estate	(6,579)
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	42,760
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	0
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Fair Value Disclosure	33,354	31,662
Available-for-sale Securities	7,933	9,974
Interest Rate Cash Flow Hedge Asset at Fair Value	17,482	14,515
Total	58,769	56,151
Interest Rate Cash Flow Hedge Liability at Fair Value	(5,491)	(177)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Fair Value Disclosure	33,354	31,662
Available-for-sale Securities	0	0
Interest Rate Cash Flow Hedge Asset at Fair Value	0	0
Total	33,354	31,662
Interest Rate Cash Flow Hedge Liability at Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Fair Value Disclosure	0	0
Available-for-sale Securities	7,933	9,974
Interest Rate Cash Flow Hedge Asset at Fair Value	17,482	14,515
Total	25,415	24,489
Interest Rate Cash Flow Hedge Liability at Fair Value	(5,491)	(177)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Fair Value Disclosure	0	0
Available-for-sale Securities	0	0
Interest Rate Cash Flow Hedge Asset at Fair Value	0	0
Total	0	0
Interest Rate Cash Flow Hedge Liability at Fair Value	$ 0	$ 0