Investments Fair Value Option Investment (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Feb. 14, 2017	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016	Feb. 01, 2017
Gain (Loss) on Investments [Line Items]
Assets, Current		$ 786,862		$ 786,862		$ 1,091,936
Revenue		662,619	$ 723,760	1,336,245	$ 1,422,195
Fair Value, Option, Changes in Fair Value, Gain (Loss)		(1,448)	(4,607)	(1,145)	(5,707)
Gross Profit		328,067	315,377	637,518	635,479
Other Assets, Noncurrent		17,457		17,457		23,484
Liabilities, Current		953,407		953,407		1,213,051
Liabilities, Noncurrent		101,978		101,978		99,628
GroupMax [Member]
Gain (Loss) on Investments [Line Items]
Equity method investments		500		500		3,900
Fair Value, Option, Changes in Fair Value, Gain (Loss)		(1,300)	(3,300)	(3,400)	(4,300)
Monster LP [Member]
Gain (Loss) on Investments [Line Items]
Equity method investments		80,900		80,900		$ 78,700
Fair Value, Option, Changes in Fair Value, Gain (Loss)		$ 100	1,300	$ 2,300	$ 1,400
Fair Value Inputs, Discount Rate				22.00%		22.00%
Fair-Value Option Investments, Recapitalization Transaction, Ownership Percentage							9.00%
Monster LP [Member]
Gain (Loss) on Investments [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)			$ (4,607)
Capital Unit, Class B [Member] | Monster LP [Member]
Gain (Loss) on Investments [Line Items]
Fair-Value Option Investment, Recapitalization Transaction, Shares Exchanged	61,484,539
Capital Unit, Class A-1 [Member] | Monster LP [Member]
Gain (Loss) on Investments [Line Items]
Fair-Value Option Investment, Recapitalization Transaction, Shares Issued	16,609,195
Fair-Value Option Investments, Recapitalization Transaction, Ownership Percentage							57.00%
Fair-Value Option Investments, Recapitalization Transaction, Liquidation Preference	$ 85,000
All Equityholders [Member] | Capital Unit, Class A-1 [Member] | Monster LP [Member]
Gain (Loss) on Investments [Line Items]
Fair-Value Option Investments, Recapitalization Transaction, Liquidation Preference	$ 150,000
Minimum [Member] | Capital Unit, Class A-1 [Member] | Monster LP [Member]
Gain (Loss) on Investments [Line Items]
Stock or Units Available for Distributions	950,000,000
Maximum [Member] | Capital Unit, Class A-1 [Member] | Monster LP [Member]
Gain (Loss) on Investments [Line Items]
Stock or Units Available for Distributions	1,494,000,000