Condensed Consolidated Unaudited Statements of Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Condensed Consolidated Unaudited Statements of Shareholders' Equity
Dividends on common stock	$ 0.46	$ 0.46

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