Pension Plans and Other Postretirement Benefits (Details 7) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($)
Defined Benefit Plan [Member]
Minimum funding requirement for 2016	$ 0
Expected contributions (approximations) for the year ended December 31, 2016 as of the time of this Form 10-K (1)	0	[1]
Supplemental Defined Benefit Plans [Member]
Minimum funding requirement for 2016	0
Expected contributions (approximations) for the year ended December 31, 2016 as of the time of this Form 10-K (1)	$ 1,319	[1]

[1] HMEC’s Annual Report on Form 10-K for the year ended December 31, 2015.