Employee Benefit Plan - Narrative (Details) - USD ($)	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017
Retirement Benefits [Abstract]
Amortization of amounts previously recognized in accumulated other comprehensive income	$ 982,000	$ 686,000
Contribution to pension plan	$ 0	$ 1,800,000

Amount after tax and reclassification adjustments, of (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement defined benefit plans.

No definition available.

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Balance Type:	debit
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