Statement of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Revenue
Natural gas transportation	$ 435,238	$ 428,656	$ 430,730
Natural gas storage	14,268	15,975	12,852
Other	(24)	(209)	36
Total operating revenues	449,482	444,422	443,618
OPERATING EXPENSES:
General and administrative	47,695	51,665	50,653
Operation and maintenance	69,970	81,736	75,237
Depreciation and amortization	112,004	107,951	106,073
Regulatory debits	1,148	1,107	2,334
Taxes, other than income taxes	16,290	14,388	17,507
Regulatory charges resulting from tax rate changes	23,580	23,580	35,680
Other expenses, net	(38)	47	444
Costs and Expenses	270,649	280,474	287,928
OPERATING INCOME	178,833	163,948	155,690
OTHER (INCOME) AND OTHER EXPENSES:
Interest expense	29,712	29,232	27,987
Allowance for equity and borrowed funds used during construction	(669)	(3,418)	(2,183)
Miscellaneous other (income) expenses, net	(1,296)	(4,533)	(1,575)
Total other (income) and other expenses	27,747	21,281	24,229
NET INCOME	$ 151,086	$ 142,667	$ 131,461