Commitments and contingencies (Details) $ in Thousands		Jun. 30, 2015 USD ($)
Commitments and Contingencies Disclosure [Line Items]
2015	[1]	$ 22,292
2016		4,105
2017		2,447
2018		0
Thereafter		0
Total		28,844
Obligations for investment contracts [Member]
Commitments and Contingencies Disclosure [Line Items]
2015	[1],[2]	0
2016	[2]	3,256
2017	[2]	2,442
2018	[2]	0
Thereafter	[2]	0
Total	[2]	5,698
Obligations for purchasing and service agreements [Member]
Commitments and Contingencies Disclosure [Line Items]
2015	[1]	22,292
2016		849
2017		5
2018		0
Thereafter		0
Total		$ 23,146

[1] Remaining 6 months in 2015.

[2] Capital Commitment to the Venture Fund