Ownership Interests in and Advances to Partner Companies and Funds - Summarized Balance Sheets for Equity Method Investments (Details) $ in Thousands	Dec. 31, 2016 USD ($) partner_company	Dec. 31, 2015 USD ($) partner_company
High Traction Stage [Member]
Summarized Equity Method Investee Disclosures [Line Items]
Current assets	$ 229,756	$ 213,884
Non-current assets	106,555	89,987
Total assets	336,311	303,871
Current liabilities	215,622	192,025
Non-current liabilities	110,315	74,208
Shareholders’ equity	10,374	37,638
Total liabilities and shareholders’ equity	$ 336,311	$ 303,871
Number of partner companies | partner_company	5	6
Expansion Stage [Member]
Summarized Equity Method Investee Disclosures [Line Items]
Current assets	$ 66,204	$ 84,041
Non-current assets	17,756	16,762
Total assets	83,960	100,803
Current liabilities	40,660	40,268
Non-current liabilities	14,851	27,449
Shareholders’ equity	28,449	33,086
Total liabilities and shareholders’ equity	$ 83,960	$ 100,803
Number of partner companies | partner_company	7	7
Initial Revenue Stage [Member]
Summarized Equity Method Investee Disclosures [Line Items]
Current assets	$ 73,698	$ 59,738
Non-current assets	4,915	2,705
Total assets	78,613	62,443
Current liabilities	29,431	21,399
Non-current liabilities	33,385	9,172
Shareholders’ equity	15,797	31,872
Total liabilities and shareholders’ equity	$ 78,613	$ 62,443
Number of partner companies | partner_company	17	15