The fee, expressed as a percentage of the credit facility, for the unused portion of the credit facility.

No definition available.

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Amount of assets pledged to secure a debt instrument.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the remainder of the fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

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Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

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Borrowing Arrangements - Term Loan Credit Facility (Details) - Secured Debt - USD ($)					12 Months Ended
	Jun. 01, 2018	Dec. 01, 2017	Jun. 01, 2017	Dec. 01, 2016	Dec. 31, 2018	Dec. 31, 2016
Term loan credit facility
Amount of senior secured draw term loan credit facility						$ 100,000,000.0
Scheduled draws on the credit facility	$ 25,000,000	$ 25,000,000	$ 25,000,000	$ 25,000,000
Total amount drawn on the credit facility					$ 100,000,000
Repayment period of credit facility					28 years
Fixed interest rate of credit facility					4.35%
Quarterly commitment fee on the unused portion of the credit facility					0.08%
Fair value of bonds pledged as collateral on the credit facility					$ 114,300,000
Principal payments due in 2019					1,870,000
Principal payments due in 2020					1,953,000
Principal payments due in 2021					2,040,000
Principal payments due in 2022					2,130,000
Principal payments due in 2023					2,225,000
Principal payments due after 2023					$ 89,782,000