Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: 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

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- Definition

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

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- Definition

Amount, after accumulated amortization, of debt discount.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28541-108399

Reference 2: 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

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- Definition

Date the credit facility terminates, in CCYY-MM-DD format.

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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.

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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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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.

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Debt (Details) - USD ($) $ in Thousands	9 Months Ended
Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Debt [Abstract]
Total long-term debt	$ 91,701		$ 87,488
Less discount on issuance of long-term debt	(218)		(226)
Less unamortized debt issuance costs	(2,509)		(2,609)
Less current maturities	(44)		(44)
Long-term portion	88,930		84,609
10.17% Senior Notes, Series A, due 2019 [Member]
Debt [Abstract]
Total long-term debt	$ 6,000		6,000
Interest rate	10.17%
9.60% Senior Notes, Series B, due 2019 [Member]
Debt [Abstract]
Total long-term debt	$ 5,000		5,000
Interest rate	9.60%
1.00% Pennvest Note, due 2019 [Member]
Debt [Abstract]
Total long-term debt	$ 85		118
Interest rate	1.00%
10.05% Senior Notes, Series C, due 2020 [Member]
Debt [Abstract]
Total long-term debt	$ 6,500		6,500
Interest rate	10.05%
8.43% Senior Notes, Series D, due 2022 [Member]
Debt [Abstract]
Total long-term debt	$ 7,500		7,500
Interest rate	8.43%
Variable Rate Pennsylvania Economic Development Financing Authority Exempt Facilities Revenue Refunding Bonds, Series 2008A, due 2029 [Member]
Debt [Abstract]
Total long-term debt	$ 12,000		12,000
4.75% York County Industrial Development Authority Revenue Bonds, series 2006, due 2036 [Member]
Debt [Abstract]
Total long-term debt	$ 10,500		10,500
Interest rate	4.75%
4.50% Pennsylvania Economic Development Financing Authority Exempt Facilities Revenue Refunding Bonds, Series 2014, due 2038 [Member]
Debt [Abstract]
Total long-term debt	$ 14,870		14,870
Interest rate	4.50%
5.00% Monthly Senior Notes, Series 2010A, due 2040 [Member]
Debt [Abstract]
Total long-term debt	$ 15,000		15,000
Interest rate	5.00%
4.00% - 4.50% York County Industrial Development Authority Exempt Facilities Revenue Bonds, Series 2015, due 2029 - 2045 [Member]
Debt [Abstract]
Total long-term debt	$ 10,000		10,000
4.00% - 4.50% York County Industrial Development Authority Exempt Facilities Revenue Bonds, Series 2015, due 2029 - 2045 [Member] \| Maximum [Member]
Debt [Abstract]
Interest rate	4.50%
4.00% - 4.50% York County Industrial Development Authority Exempt Facilities Revenue Bonds, Series 2015, due 2029 - 2045 [Member] \| Minimum [Member]
Debt [Abstract]
Interest rate	4.00%
Committed Line of Credit, due 2019 [Member]
Debt [Abstract]
Total long-term debt	$ 4,246		$ 0
First Line of Credit [Member]
Debt [Abstract]
Renewed line of credit		$ 13,000
Maturity date	May 31, 2019
Second Line of Credit [Member]
Debt [Abstract]
Renewed line of credit		11,000
Maturity date	May 31, 2019
Third Line of Credit [Member]
Debt [Abstract]
Renewed line of credit		$ 7,500
Maturity date	Jun. 30, 2018
Fourth Line of Credit [Member]
Debt [Abstract]
Renewed line of credit	$ 10,000
Maturity date	Sep. 30, 2018