Pension Plans and Other Postretirement Benefits (Details 3) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Fair value hierarchy for the Company's defined benefit pension plan assets
Total	$ 35,722		$ 32,614
United States [Member]
Fair value hierarchy for the Company's defined benefit pension plan assets
Total	14,730	[1]	13,199	[1]
International [Member]
Fair value hierarchy for the Company's defined benefit pension plan assets
Total	3,579	[1]	3,290	[1]
Fixed Income Funds [Member]
Fair value hierarchy for the Company's defined benefit pension plan assets
Total	17,413		16,125
Level 1 [Member]
Fair value hierarchy for the Company's defined benefit pension plan assets
Total	0		0
Level 1 [Member] | United States [Member]
Fair value hierarchy for the Company's defined benefit pension plan assets
Total	0	[1]	0	[1]
Level 1 [Member] | International [Member]
Fair value hierarchy for the Company's defined benefit pension plan assets
Total	0	[1]	0	[1]
Level 1 [Member] | Fixed Income Funds [Member]
Fair value hierarchy for the Company's defined benefit pension plan assets
Total	0		0
Level 2 [Member]
Fair value hierarchy for the Company's defined benefit pension plan assets
Total	35,722		32,614
Level 2 [Member] | United States [Member]
Fair value hierarchy for the Company's defined benefit pension plan assets
Total	14,730	[1]	13,199	[1]
Level 2 [Member] | International [Member]
Fair value hierarchy for the Company's defined benefit pension plan assets
Total	3,579	[1]	3,290	[1]
Level 2 [Member] | Fixed Income Funds [Member]
Fair value hierarchy for the Company's defined benefit pension plan assets
Total	17,413		16,125
Level 3 [Member]
Fair value hierarchy for the Company's defined benefit pension plan assets
Total	0		0
Level 3 [Member] | United States [Member]
Fair value hierarchy for the Company's defined benefit pension plan assets
Total	0	[1]	0	[1]
Level 3 [Member] | International [Member]
Fair value hierarchy for the Company's defined benefit pension plan assets
Total	0	[1]	0	[1]
Level 3 [Member] | Fixed Income Funds [Member]
Fair value hierarchy for the Company's defined benefit pension plan assets
Total	$ 0		$ 0

[1] None of the trust fund assets for the defined benefit pension plan have been invested in shares of HMEC’s common stock.