CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) shares in Thousands, $ in Thousands		9 Months Ended	12 Months Ended
		Dec. 31, 2015	Mar. 31, 2015	Mar. 31, 2014
Sales	[1]	$ 3,391,384	$ 3,112,659	$ 2,890,711
Cost of sales	[1]	2,717,236	2,411,756	2,600,607
Gross profit	[1]	674,148	700,903	290,104
Operating expenses:
Research and development	[1]	83,209	49,349	48,536
Selling	[1]	88,177	89,941	87,554
General and administrative	[1]	220,157	304,590	209,199
Goodwill impairment	[1],[2]	0	34,300	3,700
Gain on settlement	[1]	50,000	0	0
Income (loss) from continuing operations, before interest, income taxes and noncontrolling interest	[1]	332,605	222,723	(58,885)
Interest expense, net	[1]	(60,370)	(88,848)	(79,792)
Loss on extinguishment of debt	[1],[2]	0	(26,626)	0
Income (loss) from continuing operations, before income taxes and noncontrolling interest	[1]	272,235	107,249	(138,677)
Income taxes	[1]	86,913	37,299	(74,419)
Income (loss) from continuing operations, before noncontrolling interest	[1],[2]	185,322	69,950	(64,258)
Less net income attributable to noncontrolling interest	[1]	143	99	171
Income (loss) from continuing operations of Orbital ATK, Inc.	[1]	185,179	69,851	(64,429)
Income from discontinued operations, before income taxes	[1]	0	205,463	288,349
Income taxes	[1]	(1,008)	80,414	106,886
Income from discontinued operations	[1]	1,008	125,049	181,463
Net income attributable to Orbital ATK, Inc.	[1]	$ 186,187	$ 194,900	$ 117,034
Basic earnings (loss) per common share from:
Continuing operations (in dollars per share)	[1]	$ 3.12	$ 1.96	$ (2.03)
Discontinued operations (in dollars per share)	[1]	0.02	3.53	5.73
Basic (in dollars per share)	[1]	$ 3.14	$ 5.49	$ 3.70
Weighted-average number of common shares outstanding, basic (in shares)	[1]	59,358	35,469	31,671
Diluted earnings (loss) per common share from:
Continuing operations (in dollars per share)	[1]	$ 3.09	$ 1.93	$ (1.97)
Discontinued operations (in dollars per share)	[1]	0.02	3.46	5.55
Diluted (in dollars per share)	[1]	$ 3.11	$ 5.39	$ 3.58
Weighted-average number of common shares outstanding, diluted (in shares)	[1]	59,915	36,140	32,723
Cash dividends paid per common share	[1]	$ 0.78	$ 1.28	$ 1.10
Other comprehensive income (loss), net of tax (expense) benefit:
Net income attributable to: Orbital ATK, Inc. and noncontrolling interest	[1],[2]	$ 186,330	$ 194,999	$ 117,205
Pension and other postretirement benefits:
Prior service credits for pension and postretirement benefit plans recorded to net income, net of taxes of $8,073, $11,740 and $11,240, respectively	[1]	(13,004)	(18,906)	(18,125)
Net actuarial loss for pension and postretirement benefit plans recorded to net income, net of taxes of $(43,887), $(8,186) and $(56,791), respectively	[1]	70,550	13,841	91,387
Valuation adjustment for pension and postretirement benefit plans, net of taxes of $(2,924), $139,583, and $(48,772), respectively	[1]	4,805	(224,389)	78,522
Change in fair value of derivatives, net of taxes of $624, $(1,866) and $1,771, respectively	[1]	(986)	2,949	(2,830)
Other, net of taxes of $(231), $(151) and $(29), respectively	[1]	375	238	46
Change in cumulative translation adjustment, net of taxes of $0, $0 and $942, respectively	[1]	0	(36,796)	(1,505)
Total other comprehensive income (loss)	[1]	61,740	(263,063)	147,495
Comprehensive income (loss)	[1],[3]	248,070	(68,064)	264,700
Less comprehensive income attributable to noncontrolling interest	[1]	143	99	171
Comprehensive income (loss) attributable to Orbital ATK, Inc.	[1]	$ 247,927	$ (68,163)	$ 264,529

[1] See Note 2 - Restatement

[2] See Note 2 - Restatement

[3] See Note 2 - Restatement