REGULATORY ASSETS AND LIABILITIES (Tables)

12 Months Ended

Dec. 31, 2016

Regulatory Assets and Liabilities Disclosure [Abstract]

Schedule of Regulatory Assets

Regulatory Assets at December 31 consisted of the following items (in thousands):

	2016		2015
Environmental Remediation Costs:
Expended - Net	$	71,997	$	42,032
Liability for Future Expenditures	153,047		123,194
Deferred Asset Retirement Obligation Costs	43,014		42,430
Deferred Pension and Other Postretirement Benefit Costs	85,693		79,779
Deferred Gas Costs - Net	—		2,701
Conservation Incentive Program - Receivable	27,567		2,624
Deferred Interest Rate Contracts	7,365		7,631
Energy Efficiency Tracker	219		496
Pipeline Supplier Service Charges	2,122		3,776
Pipeline Integrity Cost	4,810		4,596
AFUDC - Equity Related Deferrals	12,434		11,423
Other Regulatory Assets	2,478		2,752
Total Regulatory Assets	$	410,746	$	323,434

Schedule of Regulatory Liabilities

Regulatory Liabilities at December 31 consisted of the following items (in thousands):

	2016		2015
Excess Plant Removal Costs	$	28,226	$	32,644
Deferred Revenue - Net	17,800		—
Societal Benefit Costs Payable	3,095		10,197
Total Regulatory Liabilities	$	49,121	$	42,841