Fair Value of Financial Assets and Liabilities (Tables)

6 Months Ended

Jun. 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.

	June 30, 2018
			Fair Value
	Cost		Level 1		Level 2		Level 3		Total
Long-term debt, including current maturities	$	519,554	—		$	570,197	—		$	570,197
Advances for construction	185,286		—		77,626		—		77,626
Total	$	704,840	$	—	$	647,823	$	—	$	647,823

	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