Earnings per share (Details) (USD $)	3 Months Ended	6 Months Ended
Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Basic
Distributed earnings (in dollars per share)	$ 0.31	$ 0.31	$ 0.62	$ 0.62
Undistributed earnings (loss) (in dollars per share)	$ 0.09	$ (0.03)	$ 0.18	$ (0.04)
Earnings Per Share, basic (in dollars per share)	$ 0.40	$ 0.28	$ 0.80	$ 0.58
Diluted
Distributed earnings (in dollars per share)	$ 0.31	$ 0.31	$ 0.62	$ 0.62
Undistributed earnings (losses) (in dollars per share)	$ 0.09	$ (0.03)	$ 0.18	$ (0.04)
Earnings Per Share, diluted (in dollars per share)	$ 0.40	$ 0.28	$ 0.80	$ 0.58
Stock appreciation rights (SARs) \| Common stock.
Antidilutive effect of HEI common stock
Antidilutive effects of SARs shares that were not included in the computation of diluted EPS (in shares)				410,000

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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