Fair Value Measurements Fair Value, Reconciliation of Level 3 - Assets (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Purchases of Convertible Debt		$ 0	$ 0	$ 1,612	$ 0
Proceeds from Sale, Maturity and Collection of Investments				(16,561)	(1,685)
Fair Value, Option, Changes in Fair Value, Gain (Loss)		(3,955)	(1,594)	(5,100)	(7,301)
AFS Securities, Beginning Asset Value		81,439	125,018	82,584	130,725
AFS Securities, Ending Asset Value		77,484	123,424	77,484	123,424
Unrealized Gains (Losses) Still Held - Assets	[1]	(3,955)	(1,594)	(5,100)	(7,301)
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value		0	14,626	0	14,626	$ 0	$ 14,588	$ 14,788	$ 10,781
Payment of Contingent Consideration		0	0	(7,858)	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases, (Sales), Issuances, (Settlements)		0	0	(6,778)	(285)
Gain from changes in fair value of contingent consideration	[2]	0	(162)	48	4,130
Fair Value, Measurement with Unobservable Inputs, Unrealized Gain Loss	[1]	0	(162)	0	4,004
Available-for-sale Investment Transfer to Cost Method Investment		0	(4,574)	0	(4,574)
Convertible debt securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Proceeds from Maturities, Prepayments and Calls of Available-for-sale Securities		0	(1,685)	(1,843)	(1,685)
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings	[3]	218	477	1,812	714
AFS Securities, Beginning Asset Value		10,868	10,573	10,038	10,116
AFS Debt Security, (losses) included in OCI		146	566	(387)	786
AFS Securities, Ending Asset Value		11,232	9,931	11,232	9,931
Unrealized Gains (Losses) Still Held - Assets	[1]	364	1,043	1,180	1,500
Redeemable preferred shares [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
AFS Securities, Beginning Asset Value		15,923	22,343	17,444	22,834
AFS Debt Security, (losses) included in OCI		(371)	(592)	(1,892)	(1,083)
AFS Securities, Ending Asset Value		15,552	17,177	15,552	17,177
Unrealized Gains (Losses) Still Held - Assets	[1]	$ (371)	(592)	$ (1,892)	$ (1,083)
Monster LP [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Option, Changes in Fair Value, Gain (Loss)			$ (1,594)

[1] Represents the unrealized losses or gains recorded in earnings and/or other comprehensive income (loss) during the period for assets and liabilities classified as Level 3 that are still held (or outstanding) at the end of the period.

[2] Changes in the fair value of contingent consideration liabilities are classified within "Acquisition-related expense (benefit), net" on the condensed consolidated statements of operations.

[3] Represents a gain at maturity of a previously impaired convertible debt security, accretion of interest income and changes in the fair value of an embedded derivative.