Summary of Significant Accounting Policies Tax (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income and other tax expense (benefit)	$ 878	$ 478	$ 1,613
Tax Treatment Of Dividends And Distributions Ordinary Dividends	$ 1.84454	$ 1.22126	$ 0.722
Tax Treatment Of Dividends And Distributions Long Term Capital Gain	0.21423	0.18959	9.176
Tax Treatment Of Dividends And Distributions Unrecaptured Section Twelve Hundred And Fifty Gain	0.06498	0.10040	3.117
Dividends and distributions declared per Common Share outstanding	$ 2.12375	$ 1.51125	$ 13.015
Income, Franchise, and Exise Taxes [Member]
Income and other tax expense (benefit)	$ 878	$ 478	$ 1,613
Discontinued operations, net			12
Provision for income, franchise and excise taxes	$ 878	$ 478	$ 1,625