Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2018

Accounting Policies [Abstract]

Disaggregation of Revenue

In the following tables, revenue from contracts with customers is disaggregated by class of customers for the three and nine month periods ended September 30, 2018 and 2017:

	Three Months Ended September 30
	2018		2017
Residential	$	138,939	$	131,608
Business	38,538		35,678
Industrial	8,987		7,919
Public authorities	12,180		11,480
Other	10,897		10,322
Total revenue from contracts with customers	$	209,541	$	197,007

	Nine Months Ended September 30
	2018		2017
Residential	$	340,107	$	309,645
Business	97,720		87,246
Industrial	24,507		21,281
Public authorities	25,875		23,500
Other	27,358		30,740
Total revenue from contracts with customers	$	515,567	$	472,412

The following tables disaggregate the Company’s non-regulated revenue by source for the three and nine month periods ended September 30, 2018 and 2017:

	Three Months Ended September 30
	2018		2017
Operating and maintenance revenue	$	2,816	$	1,903
Other non-regulated revenue	1,328		1,143
Non-regulated revenue from contracts with customers	$	4,144	$	3,046
Lease revenue	$	559	$	496
Total non-regulated revenue	$	4,703	$	3,542

	Nine Months Ended September 30
	2018		2017
Operating and maintenance revenue	$	8,278	$	5,870
Other non-regulated revenue	4,053		3,362
Non-regulated revenue from contracts with customers	$	12,331	$	9,232
Lease revenue	$	1,636	$	1,511
Total non-regulated revenue	$	13,967	$	10,743

The following tables disaggregate the Company’s operating revenue by source for the three and nine month periods ended September 30, 2018 and 2017:

	Three Months Ended September 30
	2018		2017
Revenue from contracts with customers	$	209,541	$	197,007
Regulatory balancing account revenue	9,442		14,724
Total operating revenue	$	218,983	$	211,731

	Nine Months Ended September 30
	2018		2017
Revenue from contracts with customers	$	515,567	$	472,412
Regulatory balancing account revenue	8,295		32,487
Total operating revenue	$	523,862	$	504,899

Schedule of Cash, Cash Equivalents, and Restricted Cash

The following table provides a reconciliation of cash, cash equivalents, and restricted cash within the Condensed Consolidated Balance Sheets that sum to the total of the same such amounts shown on the Condensed Consolidated Statements of Cash Flows:

	September 30, 2018		December 31, 2017
Cash and cash equivalents	66,421		94,776
Restricted cash (included in "taxes, prepaid expenses and other assets")	671		576
Total cash, cash equivalents, and restricted cash shown in the statements of cash flows	$	67,092	$	95,352

Schedule of New Accounting Pronouncements and Changes in Accounting Principles

The following tables show the effect of the accounting change to the Condensed Consolidated Statements of Income for the three and nine month periods ended September 30, 2017:

	Three Months Ended September 30, 2017
Condensed Consolidated Statement of Income line item	As Reported on Form 10-Q			Adjusted Balance on Form 10-Q			Increase (Decrease) from Retrospective Adoption
Administrative and general	$	24,886		$	22,749		$	(2,137	)
Income taxes	$	17,348		$	18,219		$	871
Total operating expenses	$	170,535		$	169,269		$	(1,266	)
Net operating income	$	41,196		$	42,462		$	1,266
Other components of net periodic benefit cost	$	—		$	(2,137	)	$	2,137
Income tax benefit (expense) on other income and expenses	$	(841	)	$	30		$	871
Net other income (loss)	$	1,230		$	(36	)	$	(1,266	)

	Nine Months Ended September 30, 2017
Condensed Consolidated Statement of Income line item	As Reported on Form 10-Q			Adjusted Balance on Form 10-Q			Increase (Decrease) from Retrospective Adoption
Administrative and general	$	73,931		$	66,908		$	(7,023	)
Income taxes	$	26,099		$	27,941		$	1,842
Total operating expenses	$	430,394		$	425,213		$	(5,181	)
Net operating income	$	74,505		$	79,686		$	5,181
Other components of net periodic benefit cost	$	—		$	(7,023	)	$	7,023
Income tax expense on other income and expenses	$	(2,947	)	$	(1,105	)	$	1,842
Net other income (loss)	$	4,315		$	(866	)	$	(5,181	)

The following table shows the effect of the accounting change to the Condensed Consolidated Statements of Cash Flows:

	Nine Months Ended September 30, 2017
Condensed Consolidated Statements of Cash Flows line item	As Reported on Form 10-Q			Adjusted Balance on Form 10-Q			Increase (Decrease) from Retrospective Adoption
Change in restricted cash	$	(679	)	$	—		$	679
Net cash used in investing activities	$	(183,511	)	$	(182,832	)	$	679
Change in cash, cash equivalents, and restricted cash	$	2,849		$	3,528		$	679
Cash, cash equivalents, and restricted cash at beginning of period	$	25,492		$	25,935		$	443
Cash, cash equivalents, and restricted cash at end of period	$	28,341		$	29,463		$	1,122