Condensed Consolidated Statements of Changes in Shareholders' Equity and Common Stock Equity (unaudited) - USD ($) $ in Thousands	Total	Hawaiian Electric Company, Inc. and Subsidiaries	Common stock	Common stock Hawaiian Electric Company, Inc. and Subsidiaries	Premium on capital stock Hawaiian Electric Company, Inc. and Subsidiaries	Retained Earnings	Retained Earnings Hawaiian Electric Company, Inc. and Subsidiaries	Accumulated other comprehensive income (loss)	Accumulated other comprehensive income (loss) Hawaiian Electric Company, Inc. and Subsidiaries
Beginning Balance at Dec. 31, 2016	$ 2,066,753	$ 1,799,787	$ 1,660,910	$ 106,818	$ 601,491	$ 438,972	$ 1,091,800	$ (33,129)	$ (322)
Beginning Balance (in shares) at Dec. 31, 2016			108,583,000	16,020,000
Increase (decrease) in stockholders' equity
Net income for common stock	34,193	21,465				34,193	21,465
Other comprehensive income (loss), net of tax (benefits)	985	459						985	459
Issuance of common stock, net of expenses	(2,630)		$ (2,630)
Issuance of common stock, net of expenses (in shares)			162,000
Common stock dividends	(33,713)	(21,942)				(33,713)	(21,942)
Ending Balance at Mar. 31, 2017	2,065,588	1,799,769	$ 1,658,280	$ 106,818	601,491	439,452	1,091,323	(32,144)	137
Ending Balance (in shares) at Mar. 31, 2017			108,745,000	16,020,000
Beginning Balance at Dec. 31, 2017	$ 2,097,386	1,845,283	$ 1,662,491	$ 107,634	614,675	476,836	1,124,193	(41,941)	(1,219)
Beginning Balance (in shares) at Dec. 31, 2017	108,787,807		108,788,000	16,142,000
Increase (decrease) in stockholders' equity
Net income for common stock	$ 40,247	27,475				40,247	27,475
Other comprehensive income (loss), net of tax (benefits)	(12,773)	31						(12,773)	31
Issuance of common stock, net of expenses	658		$ 658
Issuance of common stock, net of expenses (in shares)			53,000
Common stock dividends	(33,741)	(25,826)				(33,741)	(25,826)
Common stock issuance expenses		(8)			(8)
Ending Balance at Mar. 31, 2018	$ 2,091,777	$ 1,846,955	$ 1,663,149	$ 107,634	$ 614,667	$ 483,342	$ 1,125,842	$ (54,714)	$ (1,188)
Ending Balance (in shares) at Mar. 31, 2018	108,841,157		108,841,000	16,142,000