Organization, Basis of Presentation and Recent Accounting Pronouncements (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Feb. 12, 2015 campus
Percentage of ownership indicating control for consolidation purposes	more than 50%
Net Cash Provided by (Used in) Investing Activities	$ (52,831)	$ (8,663)
Net Cash Provided by (Used in) Operating Activities	(45,871)	99,621
Television Broadcasting [Member]
Number of television broadcast stations	5
Revision Adjustment [Member]
Net Cash Provided by (Used in) Investing Activities		(22,566)
Net Cash Provided by (Used in) Operating Activities		$ 22,566
KHE Campuses [Member] \| Higher Education [Member]
Number of nationally accredited ground campuses			38

The number of nationally accredited ground campuses to be sold.

No definition available.

Name:	ghc_NumberOfNationallyAccreditedGroundCampusesToBeSold
Namespace Prefix:	ghc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of television broadcast stations owned by the Company.

+ References

No definition available.

+ Details

Name:	ghc_NumberOfTelevisionBroadcastStationsOwned
Namespace Prefix:	ghc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Defines percentage of ownership required in the Company's domestic and foreign subsidiaries for consolidation of assets, liabilities, results of operations and cash flows of the Company.

+ References

No definition available.

+ Details

Name:	ghc_PercentageOfOwnershipIndicatingControlForConsolidationPurposes
Namespace Prefix:	ghc_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of cash inflow (outflow) from investing activities, including discontinued operations. Investing activity cash flows include making and collecting loans and acquiring and disposing of debt or equity instruments and property, plant, and equipment and other productive assets.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 24

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3521-108585

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 26

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3574-108585

+ Details

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

- Definition

Amount of cash inflow (outflow) from operating activities, including discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 24

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3521-108585

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 25

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3536-108585

+ Details

Name:	us-gaap_NetCashProvidedByUsedInOperatingActivities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	dei_LegalEntityAxis=ghc_KHECampusesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ghc_TelevisionBroadcastingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=us-gaap_ScenarioAdjustmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: