Equity Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Aug. 03, 2017
Class of Stock [Line Items]
Common Stock, Dividends, Per Share, Declared	$ 0.58	$ 0.36	$ 1.16	$ 0.72
Common Class C, Non-Voting [Member]
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount					$ 5.4