Investment in Unconsolidated Joint Ventures (Austin 300 Colorado Project, LP) (Details) ft² in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) ft²	Dec. 31, 2018 USD ($)
Schedule of Equity Method Investments [Line Items]
Aggregate outstanding indebtedness to third parties	$ 165,039	$ 342,892
Austin 300 Colorado Project, LP
Schedule of Equity Method Investments [Line Items]
Square footage of real estate property (square feet) | ft²	358
Ownership interest percentage	50.00%
Aggregate outstanding indebtedness to third parties	$ 21,430	$ 0
Cash balance of joint venture	$ 593
Austin 300 Colorado Project, LP | LIBOR
Schedule of Equity Method Investments [Line Items]
Basis spread on variable rate (percent)	2.25%
Austin 300 Colorado Project, LP | 3CB
Schedule of Equity Method Investments [Line Items]
Ownership interest percentage	34.50%
Austin 300 Colorado Project, LP | 3CRR
Schedule of Equity Method Investments [Line Items]
Ownership interest percentage	15.50%
Construction Loans | Austin 300 Colorado Project, LP
Schedule of Equity Method Investments [Line Items]
Maximum borrowing capacity	$ 126,000