Income Taxes (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Sep. 30, 2017	Oct. 01, 2016	Dec. 31, 2016
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Income tax provision (benefit)	$ (331,000)	$ 971,000	$ 234,000	$ 7,410,000
Statutory income tax rate	35.00%
Unrecognized tax benefits that could significantly change during the next twelve months	$ 1,400,000		1,400,000
Unrecognized tax benefits, associated interest and penalties that could significantly change within the next twelve months	100,000		100,000
Total potential decrease in UTB	1,500,000		1,500,000
Tax credit carryforward, amount					$ 105,900,000
Deferred tax assets, valuation allowance	24,200,000		$ 24,200,000
U.S. Federal
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Statutory income tax rate			35.00%
Bermuda
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Income tax provision (benefit)			$ 0
Statutory income tax rate			0.00%
Internal Revenue Service (IRS)
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Operating loss carryforwards					367,000,000
Tax credit carryforward, amount					49,200,000
State and Local Jurisdiction
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Operating loss carryforwards					193,300,000
Tax credit carryforward, amount					56,700,000
Other Long-term Liabilities
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Uncertain tax positions	$ 27,100,000		$ 27,100,000		29,600,000
No Expiration Date
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Tax credit carryforward, amount					$ 55,500,000