Reconciliation of tax charge at statutory tax rate to provision for income taxes (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Income Tax Disclosure [Abstract]
Earnings/(losses) before provision for income taxes and earnings from unconsolidated companies, net of tax	$ (14,992)		$ 8,101		$ (4,637)
Tax charge at statutory rate of Nil%	0	[1]	0	[1]	0	[1]
Exchange rate movements on deferred tax	(3,207)		83		(2,094)
Other permanent items	674		2,943		106
Change in valuation allowance	13,015		6,093		11,795
Difference in taxation rates	7,353		11,421		9,067
Change in provisions for uncertain tax positions	(1,788)		(174)		817
Change in tax rates	(276)		600		(222)
Deferred tax charge for derivatives	2,119		0		0
Other	(262)		685		142
Provision for income taxes	$ 17,628		$ 21,651		$ 19,611
Statutory tax rate, percentage	0.00%		0.00%		0.00%

[1] The Company is resident in Bermuda, which does not impose an income tax.