Subsequent Events	9 Months Ended
Dec. 31, 2015
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events (unaudited) As a result of the Restatement, the Company was unable to file its Quarterly Reports on Form 10-Q with the SEC for the fiscal quarters ended July 3, 2016 and October 2, 2016 ("the 2016 Quarterly Reports"). The Company has entered into an extension agreement with its Senior Credit Facility lender group to extend, until April 14, 2017, the deadline under the Senior Credit Facility for filing with the SEC the 2016 Quarterly Reports, as well as an amended Form 10-Q for the fiscal quarter ended April 3, 2016 and the Company's Annual Report on Form 10-K for 2016. As a result of the extension, the Company is in compliance with the financial covenants as of the date of the filing of this Form 10-K/A based on the Company's restated financial results. On August 12, 2016, a putative class action complaint, naming the Company, our Chief Executive Officer and our Chief Financial Officer as defendants, was filed in the United States District Court for the Eastern District of Virginia (Steven Knurr v. Orbital ATK, Inc., et al., No. 16-cv-01031 (TSE-MSN)). The class action complaint asserts claims on behalf of purchasers of Orbital securities for violations of Sections 10(b) and 20(a) of the Securities Exchange Act of 1934 and Rule 10b-5 thereunder, arising out of allegedly false and misleading statements and the failure to disclose that: (i) the Company lacked effective control over financial reporting; and (ii) as a result, the Company failed to record an anticipated loss on its long-term contract with the U.S. Army to manufacture and supply small caliber ammunition at the U.S. Army’s Lake City Army Ammunition Plant. The complaint seeks a determination that this matter is a proper class action and certifying the plaintiff as the class representative, an award of damages, an award of reasonable costs and expenses of trial, including counsel and expert fees, and an award of such other relief as deemed appropriate by the Court. The Company intends to defend this action vigorously. SEC Investigation The SEC is conducting a non-public investigation relating to our historical accounting practices as a result of the prior restatement of the Company’s unaudited condensed consolidated financial statements for the quarterly periods ended July 5, 2015 and October 4, 2015 described in the Original Filing, and the Company also has voluntarily self-reported to the SEC regarding matters pertaining to the Restatement described in this Form 10-K/A. The Company is cooperating fully with the SEC in connection with these matters.

Subsequent Events (unaudited)

As a result of the Restatement, the Company was unable to file its Quarterly Reports on Form 10-Q with the SEC for the fiscal quarters ended July 3, 2016 and October 2, 2016 ("the 2016 Quarterly Reports"). The Company has entered into an extension agreement with its Senior Credit Facility lender group to extend, until April 14, 2017, the deadline under the Senior Credit Facility for filing with the SEC the 2016 Quarterly Reports, as well as an amended Form 10-Q for the fiscal quarter ended April 3, 2016 and the Company's Annual Report on Form 10-K for 2016. As a result of the extension, the Company is in compliance with the financial covenants as of the date of the filing of this Form 10-K/A based on the Company's restated financial results.

On August 12, 2016, a putative class action complaint, naming the Company, our Chief Executive Officer and our Chief Financial Officer as defendants, was filed in the United States District Court for the Eastern District of Virginia (Steven Knurr v. Orbital ATK, Inc., et al., No. 16-cv-01031 (TSE-MSN)). The class action complaint asserts claims on behalf of purchasers of Orbital securities for violations of Sections 10(b) and 20(a) of the Securities Exchange Act of 1934 and Rule 10b-5 thereunder, arising out of allegedly false and misleading statements and the failure to disclose that: (i) the Company lacked effective control over financial reporting; and (ii) as a result, the Company failed to record an anticipated loss on its long-term contract with the U.S. Army to manufacture and supply small caliber ammunition at the U.S. Army’s Lake City Army Ammunition Plant. The complaint seeks a determination that this matter is a proper class action and certifying the plaintiff as the class representative, an award of damages, an award of reasonable costs and expenses of trial, including counsel and expert fees, and an award of such other relief as deemed appropriate by the Court. The Company intends to defend this action vigorously.

SEC Investigation

The SEC is conducting a non-public investigation relating to our historical accounting practices as a result of the prior restatement of the Company’s unaudited condensed consolidated financial statements for the quarterly periods ended July 5, 2015 and October 4, 2015 described in the Original Filing, and the Company also has voluntarily self-reported to the SEC regarding matters pertaining to the Restatement described in this Form 10-K/A. The Company is cooperating fully with the SEC in connection with these matters.