Business Combination (Details)	3 Months Ended
	Sep. 30, 2014
Business Combination [Abstract]
Date of Merger Transaction Agreement	Apr. 28, 2014
Each Share of Orbital's common stock converted to shares of ATK common stock prior to closing of merger	0.449
Percent owned by Orbital's stockholders of Orbital ATK	46.20%
Percent owned by ATK's stockholders of Orbital ATK	53.80%