Fair Value of Financial Assets and Liabilities (Tables)

9 Months Ended

Sep. 30, 2018

Fair Value Disclosures [Abstract]

Schedule of fair value of long-term debt, including current maturities and advances for construction

Advances for construction fair values were estimated using broker quotes from companies that frequently purchase these investments.

	September 30, 2018
			Fair Value
	Cost		Level 1		Level 2		Level 3		Total
Long-term debt, including current maturities	$	819,122	—		$	847,812	—		$	847,812
Advances for construction	186,897		—		77,745		—		77,745
Total	$	1,006,019	$	—	$	925,557	$	—	$	925,557

	December 31, 2017
			Fair Value
	Cost		Level 1		Level 2		Level 3		Total
Long-term debt, including current maturities	$	531,713	$	—	$	607,492	$	—	$	607,492
Advances for construction	182,502		—		75,083		—		75,083
Total	$	714,215	—		$	682,575	$	—	$	682,575