Taxation (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Mar. 31, 2015
Operating Loss Carryforwards [Line Items]
Change in valuation allowance	$ 900	$ (43,800)	$ 5,600
Valuation allowance	18,776	17,852
Income taxes paid (refunded)	(1,100)	10,300	1,100
Unrecognized tax benefits	0	0
Interest and penalties accrued on unrecognized tax benefits	0	$ 0
Internal Revenue Service (IRS)
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	91,400
U.S.
Operating Loss Carryforwards [Line Items]
Valuation allowance			$ 48,500	$ 1,000
Ireland
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	10,400
U.K.
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	90,900
Singapore
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 7,600
U.S. | Internal Revenue Service (IRS)
Operating Loss Carryforwards [Line Items]
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate, Dividend Withholding Tax, Percent	5.00%