Fair Value Measurements Unobservable Inputs Reconciliation - Assets (Details) - Fair Value, Measurements, Recurring - Level 3 - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 43,130	$ 46,133	$ 48,406	$ 42,512
Purchases	5,108	5,239	5,108	10,538
Sales	(7,617)	(4,254)	(10,507)	(6,228)
Realized gain on sale	0	(129)	0	(129)
Unrealized gains	0	1,478	619	3,936
Unrealized losses	(1,230)	(1,402)	(4,235)	(3,564)
Balance at end of period	39,391	47,065	39,391	47,065
Investments in Associated Companies
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	2,298	2,131	2,163	2,243
Purchases	0	0	0	0
Sales	0	0	0	0
Realized gain on sale	0		0	0
Unrealized gains	0	0	135	0
Unrealized losses	(27)	(51)	(27)	(163)
Balance at end of period	2,271	2,080	2,271	2,080
Other Investments - Related Party
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	7,296	10,226	9,623	10,228
Purchases	0	0	0	0
Sales	(7,258)	(1,496)	(9,985)	(1,496)
Realized gain on sale	0		0	0
Unrealized gains	0	1,478	484	1,476
Unrealized losses	(38)	(3)	(122)	(3)
Balance at end of period	0	10,205	0	10,205
ModusLink Warrants
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	2,163	3,385	2,199	5,832
Purchases	0	0	0	0
Sales	0	0	0	0
Realized gain on sale	0		0	0
Unrealized gains	0	0	0	0
Unrealized losses	(527)	(951)	(563)	(3,398)
Balance at end of period	1,636	2,434	1,636	2,434
Marketable Securities and Other
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	31,373	30,391	34,421	24,209
Purchases	5,108	5,239	5,108	10,538
Sales	(359)	(2,758)	(522)	(4,732)
Realized gain on sale	0	(129)	0	(129)
Unrealized gains	0	0	0	2,460
Unrealized losses	(638)	(397)	(3,523)	0
Balance at end of period	$ 35,484	$ 32,346	$ 35,484	$ 32,346