Capital Stock, Stock Awards, and Stock Options Capital Stock, Stock Awards, and Stock Options (Antidilutive Shares) (Details 6) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Antidilutive Shares [Abstract]
Weighted average restricted stock	62ghc_AntidilutiveRestrictedStock	83ghc_AntidilutiveRestrictedStock	44ghc_AntidilutiveRestrictedStock

Additional shares excluded in the calculation of diluted EPS as a result of the antidilutive effect of restricted stock using the treasury stock method.

No definition available.

Name:	ghc_AntidilutiveRestrictedStock
Namespace Prefix:	ghc_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration