Long-Term Debt - Outstanding Long-Term Debt (Detail) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Total long-term debt		$ 145,800	$ 145,900
Capital lease obligation		3,125	3,471
Total Long-term debt		148,648	149,053
Less: current maturities		(12,111)	(12,099)
Less: debt issuance costs		(280)	(291)
Total long-term debt, net of current maturities		136,537	136,954
9.08% bond, due June 1, 2022 [Member]
Debt Instrument [Line Items]
Total long-term debt	[1]	7,979	7,978
6.64% note, due October 31, 2017 [Member]
Debt Instrument [Line Items]
Total long-term debt		2,727	2,727
5.50% note, due October 12, 2020 [Member]
Debt Instrument [Line Items]
Total long-term debt		8,000	8,000
5.93% note, due October 31, 2023 [Member]
Debt Instrument [Line Items]
Total long-term debt		21,000	21,000
5.68% note, due June 30, 2026 [Member]
Debt Instrument [Line Items]
Total long-term debt		29,000	29,000
Uncollateralized Senior Notes Due On May Two Thousand Twenty Eight [Member]
Debt Instrument [Line Items]
Total long-term debt		7,000	7,000
Uncollateralized Senior Note Two Due on December Two Thousand Twenty Eight [Member]
Debt Instrument [Line Items]
Total long-term debt		20,000	20,000
Uncollateralized Senior Notes Due On Two Thousand Twenty Nine [Member]
Debt Instrument [Line Items]
Total long-term debt		50,000	50,000
Promissory note [Member]
Debt Instrument [Line Items]
Total long-term debt		$ 97	$ 168

[1] FPU secured first mortgage bonds are guaranteed by Chesapeake Utilities.