CONSOLIDATED STATEMENT OF CHANGES IN EQUITY (Parentheticals) - $ / shares	3 Months Ended			6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2019
Consolidated Statement of Changes in Equity (Parenthetical) [Abstract]
Cash dividends declared and paid, quarterly, per Class A share	$ 0.25	$ 0.210	$ 0.195	$ 0.25