Income Taxes Schedule of Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Effective Tax Rate [Line Items]
Income Tax Reconciliation, Permanent Differences and Other Adjustments	0.04%	(1.58%)	0.05%
Income Tax Reconciliation, Discrete Items	0.26%	(24.97%)	(0.22%)
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent	(53.55%)	0.00%	0.00%
Effective income tax rate	(35.84%)	0.82%	3.07%
BERMUDA
Effective Tax Rate [Line Items]
Foreign income taxed at other than the statutory rate	(0.00%)	(0.00%)	(0.00%)
UNITED STATES
Effective Tax Rate [Line Items]
Effective income tax rate	17.10%	41.68%	3.01%
Uncertain tax position [Member]
Effective Tax Rate [Line Items]
Effective income tax rate	0.21%	(10.16%)	0.00%
Foreign Tax Authority [Member]
Effective Tax Rate [Line Items]
Foreign income taxed at other than the statutory rate	0.10%	(4.15%)	0.23%