401(k) Plan (Narrative) (Detail) (Napco and Subsidiaries 401 (k) Plan [Member], USD $)	3 Months Ended		9 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013	Mar. 31, 2012
Napco and Subsidiaries 401 (k) Plan [Member]
Schedule of Deferred Compensation Plans [Line Items]
Deferred compensation plan expense	$ 27,000	$ 19,000	$ 73,000	$ 19,000