STOCK PLANS (Details 5) (USD $)	12 Months Ended
Dec. 31, 2013
$10.24 - $15.00
Range of Exercise Prices
Range of exercise prices, low end of range (in dollars per share)	$ 10.24
Range of exercise prices, high end of range (in dollars per share)	$ 15.00
Options Outstanding
Number of Options (in shares)	673,889
Weighted- Average Remaining Contractual Life (years)	2 years 8 months 23 days
Weighted Average Exercise Price (in dollars per share)	$ 11.63
Options Exercisable
Number of Options (in shares)	673,889
Weighted- Average Exercise Price (in dollars per share)	$ 11.63
$15.01 - $18.77
Range of Exercise Prices
Range of exercise prices, low end of range (in dollars per share)	$ 15.01
Range of exercise prices, high end of range (in dollars per share)	$ 18.77
Options Outstanding
Number of Options (in shares)	194,500
Weighted- Average Remaining Contractual Life (years)	2 years 3 months 22 days
Weighted Average Exercise Price (in dollars per share)	$ 17.81
Options Exercisable
Number of Options (in shares)	178,500
Weighted- Average Exercise Price (in dollars per share)	$ 17.97
$18.78 - $23.47
Range of Exercise Prices
Range of exercise prices, low end of range (in dollars per share)	$ 18.78
Range of exercise prices, high end of range (in dollars per share)	$ 23.47
Options Outstanding
Number of Options (in shares)	155,000
Weighted- Average Remaining Contractual Life (years)	3 years 1 month 10 days
Weighted Average Exercise Price (in dollars per share)	$ 22.68
Options Exercisable
Number of Options (in shares)	155,000
Weighted- Average Exercise Price (in dollars per share)	$ 22.68
$10.24 - $23.47
Range of Exercise Prices
Range of exercise prices, low end of range (in dollars per share)	$ 10.24
Range of exercise prices, high end of range (in dollars per share)	$ 23.47
Options Outstanding
Number of Options (in shares)	1,023,389
Weighted- Average Remaining Contractual Life (years)	2 years 8 months 16 days
Weighted Average Exercise Price (in dollars per share)	$ 14.48
Options Exercisable
Number of Options (in shares)	1,007,389
Weighted- Average Exercise Price (in dollars per share)	$ 14.45

Name:	knl_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeAbstract
Namespace Prefix:	knl_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Name:	knl_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOptionsExercisableAbstract
Namespace Prefix:	knl_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	knl_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOptionsOutstandingAbstract
Namespace Prefix:	knl_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.

+ References

+ Details

Name:	us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph 64

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(c)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(iii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(i)-(ii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(a, b)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices.

+ References

+ Details

Name:	us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Weighted average remaining contractual term of outstanding stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

+ Details

Name:	us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

+ Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration