Income Taxes - Statutory tax rate by jurisdiction (Details)		12 Months Ended
	Jan. 01, 2018	Dec. 31, 2019	Dec. 31, 2017
Bermuda
Income Tax Disclosure [Line Items]
Statutory tax rate (percentage)		0.00%
United States
Income Tax Disclosure [Line Items]
Statutory tax rate (percentage)	21.00%	21.00%	35.00%
United Kingdom
Income Tax Disclosure [Line Items]
Statutory tax rate (percentage)		19.00%
Ireland
Income Tax Disclosure [Line Items]
Statutory tax rate (percentage)		12.50%
Denmark
Income Tax Disclosure [Line Items]
Statutory tax rate (percentage)		22.00%
Canada
Income Tax Disclosure [Line Items]
Statutory tax rate (percentage)		26.50%
Gibraltar
Income Tax Disclosure [Line Items]
Statutory tax rate (percentage)		10.00%
Australia
Income Tax Disclosure [Line Items]
Statutory tax rate (percentage)		30.00%
Hong Kong
Income Tax Disclosure [Line Items]
Statutory tax rate (percentage)		16.50%
Netherlands
Income Tax Disclosure [Line Items]
Statutory tax rate (percentage)		19.00%