Summary of Significant Accounting Policies Tax (Parenthetical) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disclosure Summary Of Significant Accounting Policies Tax Parenthetical Details [Abstract]
Income tax refund claims or receives	$ 1.6
Term to refund carryover amount	4 years
Refund percentage available in first year	50.00%
Remaining Tax Carryover Amount	$ 1.6
Expected alternative minimum tax benefit	$ 3.2
Dividend payable common share/unit, per share	$ 0.5675	$ 0.54	$ 0.50375