Goodwill and Intangible Assets - Purchased Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 29, 2015	Mar. 30, 2014	Dec. 28, 2014
Acquired finite-lived intangible assets:
Acquired finite-lived intangible assets: Gross Value	$ 212.6		$ 212.6
Intangible assets: Accumulated Amortization	(171.8)		(167.2)
Acquired finite-lived intangible assets: Net Value	40.8us-gaap_FiniteLivedIntangibleAssetsNet		45.4us-gaap_FiniteLivedIntangibleAssetsNet
Acquired indefinite-lived intangible assets:
Intangible assets: Gross Value	219.5		219.5
Intangible assets: Net Value	47.7		52.3
Consolidated amortization expense related to intangible assets subject to amortization	4.6us-gaap_AmortizationOfIntangibleAssets	5.6us-gaap_AmortizationOfIntangibleAssets
Trade names
Acquired indefinite-lived intangible assets:
Acquired indefinite-lived intangible assets: Gross Value	6.9		6.9
Customer relationships
Acquired finite-lived intangible assets:
Acquired finite-lived intangible assets: Gross Value	99.0		99.0
Intangible assets: Accumulated Amortization	(74.2)		(70.6)
Acquired finite-lived intangible assets: Net Value	24.8		28.4
Contracts and backlog
Acquired finite-lived intangible assets:
Acquired finite-lived intangible assets: Gross Value	82.7		82.7
Intangible assets: Accumulated Amortization	(80.2)		(80.0)
Acquired finite-lived intangible assets: Net Value	2.5		2.7
Developed technology and technical know-how
Acquired finite-lived intangible assets:
Acquired finite-lived intangible assets: Gross Value	23.1		23.1
Intangible assets: Accumulated Amortization	(11.5)		(10.9)
Acquired finite-lived intangible assets: Net Value	11.6		12.2
Trade names
Acquired finite-lived intangible assets:
Acquired finite-lived intangible assets: Gross Value	6.0		6.0
Intangible assets: Accumulated Amortization	(5.1)		(5.0)
Acquired finite-lived intangible assets: Net Value	0.9		1.0
Favorable operating lease
Acquired finite-lived intangible assets:
Acquired finite-lived intangible assets: Gross Value	1.8		1.8
Intangible assets: Accumulated Amortization	(0.8)		(0.7)
Acquired finite-lived intangible assets: Net Value	$ 1.0		$ 1.1

Intangible Assets (Excluding Goodwill), Gross

No definition available.

Name:	ktos_IntangibleAssetsExcludingGoodwillGross
Namespace Prefix:	ktos_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(2)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275

+ Details

Name:	us-gaap_AmortizationOfIntangibleAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetsGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetsNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsNetAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275

+ Details

Name:	us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwillAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16212-109274

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph ((a)(1),(b))

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275

+ Details

Name:	us-gaap_IntangibleAssetsNetExcludingGoodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=ktos_ContractsAndBacklogMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=ktos_FavorableOperatingLeaseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_CustomerRelationshipsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_DevelopedTechnologyRightsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_TradeNamesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_TradeNamesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: