Debt instrument applicable margin rate.

No definition available.

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- Definition

Debt instrument covenant leverage ratio.

+ References

No definition available.

+ Details

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- Definition

Debt Instrument, Covenant, Leverage Ratio Required For Step-Down Percentage

+ References

No definition available.

+ Details

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- Definition

Debt instrument percentage of excess cash flow to be used for mandatory prepayment starting next fiscal year.

+ References

No definition available.

+ Details

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- Definition

Debt Instrument, Percentage Of Excess Cash Flow To Be Used For Mandatory Prepayment, Step-Down Percentage

+ References

No definition available.

+ Details

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- Definition

Debt instrument percentage of net cash proceeds from issuances of permitted equity securities to be used for mandatory prepayment.

+ References

No definition available.

+ Details

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- Definition

Debt instrument percentage of net cash proceeds from issuances or incurrence of additional debt to be used for mandatory prepayment.

+ References

No definition available.

+ Details

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- Definition

Debt instrument percentage of net cash proceeds from sales and dispositions subject to certain reinvestment rights.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Line of credit facility swingline sublimit.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
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Period Type:	duration

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of unamortized debt discount (premium) and debt issuance costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28555-108399

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

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.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

+ Details

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- Definition

The carrying value as of the balance sheet date of the noncurrent portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section 45
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=99376301&loc=d3e1314-112600

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section 45
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=99376301&loc=d3e1336-112600

+ Details

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

+ References

+ Details

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Period Type:	instant

- Details

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- Details

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Debt - Narrative (Detail) - USD ($)	6 Months Ended
Debt - Narrative (Detail) - USD ($)	Jun. 30, 2018	Jun. 21, 2018	Dec. 31, 2017	Dec. 22, 2016
Line of Credit Facility [Line Items]
Long-term outstanding borrowings	$ 29,176,000		$ 24,516,000
Capital Leases
Line of Credit Facility [Line Items]
Debt instrument, weighted average interest rates	4.86%
Term Loan
Line of Credit Facility [Line Items]
Debt Instrument, maximum borrowing capacity		$ 30,000,000		$ 75,000,000
Current outstanding borrowings	$ 6,600,000		3,800,000
Long-term outstanding borrowings	91,500,000		66,600,000
Unamortized transaction costs	$ 1,300,000		900,000
Debt instrument, percentage of net cash proceeds from sales and dispositions subject to certain reinvestment rights	100.00%
Debt instrument, percentage of net cash proceeds from issuances or incurrence of additional debt to be used for mandatory prepayment	100.00%
Debt instrument, percentage of excess cash flow to be used for mandatory prepayment starting next fiscal year	75.00%
Debt instrument, step-down percentage	50.00%
Debt instrument covenant leverage ratio	325.00%
Debt instrument, percentage of net cash proceeds from issuances of permitted equity securities to be used for mandatory prepayment	100.00%
Term Loan \| Minimum
Line of Credit Facility [Line Items]
Debt instrument covenant leverage ratio	275.00%
Term Loan \| Maximum
Line of Credit Facility [Line Items]
Debt instrument covenant leverage ratio	325.00%
Term Loan \| Federal Funds Rate
Line of Credit Facility [Line Items]
Debt instrument variable interest rate	0.50%
Term Loan \| LIBOR
Line of Credit Facility [Line Items]
Debt instrument variable interest rate	1.00%
Term Loan \| LIBOR \| Minimum
Line of Credit Facility [Line Items]
Debt instrument applicable margin	2.25%
Term Loan \| LIBOR \| Maximum
Line of Credit Facility [Line Items]
Debt instrument applicable margin	4.00%
Term Loan \| Base Rate \| Minimum
Line of Credit Facility [Line Items]
Debt instrument applicable margin	1.25%
Term Loan \| Base Rate \| Maximum
Line of Credit Facility [Line Items]
Debt instrument applicable margin	3.00%
Revolving Credit Facility
Line of Credit Facility [Line Items]
Debt instrument, percentage of net cash proceeds from sales and dispositions subject to certain reinvestment rights	100.00%
Debt instrument, percentage of net cash proceeds from issuances or incurrence of additional debt to be used for mandatory prepayment	100.00%
Debt instrument, percentage of excess cash flow to be used for mandatory prepayment starting next fiscal year	75.00%
Debt instrument, step-down percentage	50.00%
Debt instrument covenant leverage ratio	325.00%
Debt instrument, percentage of net cash proceeds from issuances of permitted equity securities to be used for mandatory prepayment	100.00%
Line of credit facility maximum borrowing capacity				75,000,000
Long-term outstanding borrowings	$ 29,200,000		24,500,000
Unamortized transaction costs	$ 800,000		$ 900,000
Line of credit facility, swingline sublimit				$ 10,000,000
Revolving Credit Facility \| Minimum
Line of Credit Facility [Line Items]
Debt covenant, leverage ratio required for step-down percentage	2.75
Revolving Credit Facility \| Maximum
Line of Credit Facility [Line Items]
Debt covenant, leverage ratio required for step-down percentage	3.25
Revolving Credit Facility \| Federal Funds Rate
Line of Credit Facility [Line Items]
Debt instrument variable interest rate	0.50%
Revolving Credit Facility \| LIBOR
Line of Credit Facility [Line Items]
Debt instrument variable interest rate	1.00%
Revolving Credit Facility \| LIBOR \| Minimum
Line of Credit Facility [Line Items]
Debt instrument variable interest rate	2.25%
Revolving Credit Facility \| LIBOR \| Maximum
Line of Credit Facility [Line Items]
Debt instrument variable interest rate	4.00%
Revolving Credit Facility \| Base Rate \| Minimum
Line of Credit Facility [Line Items]
Debt instrument variable interest rate	1.25%
Revolving Credit Facility \| Base Rate \| Maximum
Line of Credit Facility [Line Items]
Debt instrument variable interest rate	3.00%