Condensed Consolidated Unaudited Statements of Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended	9 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Condensed Consolidated Unaudited Statements of Shareholders' Equity
Dividends on common stock	$ 0.18	$ 0.18	$ 0.82	$ 0.82

Aggregate special dividends declared per share of common stock.

No definition available.

Name:	dit_SpecialDividendsDeclaredOnCommonStock
Namespace Prefix:	dit_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration