Annual and transition report of foreign private issuers pursuant to Section 13 or 15(d)

Income taxes (Narrative) (Details)

v3.8.0.1
Income taxes (Narrative) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Income Tax Disclosure [Line Items]      
Net deferred income tax liabilities $ 522,714 $ 363,534  
Deferred income tax assets 151,234 215,445  
Deferred income tax liabilities 673,948 578,979  
Valuation allowance on tax assets 104,858 127,361 $ 72,000
Unrecognized tax benefits $ 31,000 $ 29,800  
Statutory income tax rate 12.50% 12.50% 12.50%
Ireland      
Income Tax Disclosure [Line Items]      
Net deferred income tax liabilities $ 572,165 $ 427,914  
Valuation allowance on tax assets $ 2,928 $ 1,562  
Statutory income tax rate [1] 12.50% 12.50% 12.50%
United States      
Income Tax Disclosure [Line Items]      
Valuation allowance on tax assets $ 59,983 $ 89,130  
Statutory income tax rate [1] 35.70% 36.30% 36.30%
Federal and state statutory rate 35.70%    
Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Change In Tax Rate, Provisional Income Tax Expense (Benefit) $ 22,000    
The Netherlands      
Income Tax Disclosure [Line Items]      
Valuation allowance on tax assets $ 18,240 $ 26,758  
Statutory income tax rate [1] 25.00% 25.00% 25.00%
Carried back period 1 year    
Carry forward period 9 years    
Australia      
Income Tax Disclosure [Line Items]      
Valuation allowance on tax assets $ 23,700 $ 9,900  
[1] The local statutory income tax expense for our significant tax jurisdictions (Ireland, the United States, the Netherlands and Isle of Man) does not differ from the actual income tax expense.