Revenue Recognition - Significant Changes in the Contract Assets and Liabilities Balances (Details) - USD ($)	3 Months Ended
Mar. 31, 2019	Apr. 01, 2018
Contract Asset
Beginning Balance	$ 48,786,000	$ 45,877,000
Increases due to rights to consideration for customer specific goods produced, but not billed during the period	51,332,000	48,786,000
Transferred to receivables from contract assets recognized at the beginning of the period	(48,786,000)	(45,877,000)
Increase as a result of cumulative catch-up arising from changes in the estimate of completion, excluding amounts transferred to receivables during the period	0	0
Impairment of contract asset	0	0
Ending Balance	51,332,000	48,786,000
Contract Liability
Beginning Balance	(18,533,000)	(17,736,000)
Revenue deferred or rebates accrued	(6,928,000)	(19,730,000)
Recognized as revenue	2,098,000	1,652,000
Rebates paid to customers	8,606,000	17,281,000
Increase as a result of cumulative catch-up arising from changes in the estimate of completion, excluding amounts transferred to receivables during the period	0	0
Ending Balance	$ (14,757,000)	$ (18,533,000)

Change In Contract With Customer, Asset [Roll Forward]

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Change in Contract with Customer, Liability [Roll Forward]

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Amount of impairment loss for asset recognized from cost incurred to obtain or fulfill contract with customer.

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Amount of increase (decrease) in revenue recognized for cumulative catch-up adjustment from change in measure of progress which increases (decreases) right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time.

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Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time.

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