Summary of Significant Accounting Policies Capital Leased Asset (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Capital Leased Assets [Line Items]
Amortization of Leased Asset	$ 1,451	$ 1,401	$ 1,353
Capital Leased Assets, Noncurrent, Fair Value Disclosure	7,816	7,126
Ground Leases, Accumulated Amortization	6,506	5,056
Capital Leases, Balance Sheet, Assets by Major Class, Net	$ 1,300	$ 2,100