Fair Value Measurements (Details 1) - USD ($) $ in Thousands		Jun. 30, 2019	Dec. 31, 2018
Assets
Money Market Investments		$ 71,000	$ 75,500
Marketable equity securities		518,099	496,390
Fair Value, Recurring [Member]
Assets
Money Market Investments	[1]	71,000	75,500
Marketable equity securities	[2]	518,099	496,390
Other current investments	[3]	18,776	18,191
Interest Rate Swap	[4]	262	369
Total Financial Assets		608,137	590,450
Liabilities
Deferred compensation plan liabilities	[5]	32,901	36,080
Interest rate swap	[6]	324
Total Financial Liabilities		33,225
Fair Value, Recurring [Member] | Level 1 [Member]
Assets
Money Market Investments	[1]	0	0
Marketable equity securities	[2]	518,099	496,390
Other current investments	[3]	11,738	11,203
Interest Rate Swap	[4]	0	0
Total Financial Assets		529,837	507,593
Liabilities
Deferred compensation plan liabilities	[5]	0	0
Interest rate swap	[6]	0
Total Financial Liabilities		0
Fair Value, Recurring [Member] | Level 2 [Member]
Assets
Money Market Investments	[1]	71,000	75,500
Marketable equity securities	[2]	0	0
Other current investments	[3]	7,038	6,988
Interest Rate Swap	[4]	262	369
Total Financial Assets		78,300	82,857
Liabilities
Deferred compensation plan liabilities	[5]	32,901	$ 36,080
Interest rate swap	[6]	324
Total Financial Liabilities		$ 33,225

[1] The Company’s money market investments are included in Cash and Cash Equivalents and the value considers the liquidity of the counterparty.

[2] The Company’s investments in marketable equity securities are held in common shares of U.S. corporations that are actively traded on U.S. stock exchanges. Price quotes for these shares are readily available.

[3] Includes U.S. Government Securities, corporate bonds, mutual funds and time deposits. These investments are valued using a market approach based on the quoted market prices of the security or inputs that include quoted market prices for similar instruments and are classified as either Level 1 or Level 2 in the fair value hierarchy.

[4] Included in Deferred Charges and Other Assets. The Company utilized a market approach model using the notional amount of the interest rate swap multiplied by the observable inputs of time to maturity and market interest rates.

[5] Includes Graham Holdings Company’s Deferred Compensation Plan and supplemental savings plan benefits under the Graham Holdings Company’s Supplemental Executive Retirement Plan, which are included in accrued compensation and related benefits. These plans measure the market value of a participant’s balance in a notional investment account that is comprised primarily of mutual funds, which are based on observable market prices. However, since the deferred compensation obligations are not exchanged in an active market, they are classified as Level 2 in the fair value hierarchy. Realized and unrealized gains (losses) on deferred compensation are included in operating income.

[6] Included in Other Liabilities. The Company utilized a market approach model using the notional amount of the interest rate swap multiplied by the observable inputs of time to maturity and market interest rates.