Investments (Details-1) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Available-for-sale securities:
Cost basis	$ 2,225	$ 1,964
Gross unrealized gains	599	765
Gross unrealized losses	(2)	0
Fair Value	2,822	2,729
Equity method investments:
Equity method investments	70,650	68,872
Other Investments	159	159
Total investments	73,631	71,760
Results of Investment Liquidation [Abstract]
Proceeds from sale of investments	19	38	$ 39
Gain (loss) on sale of investments	10	21	2
ATC [Member]
Equity method investments:
Equity method investments	69,466	67,673
Other Equity Method Investments [Member]
Equity method investments:
Equity method investments	1,184	1,199
MGE [Member]
Available-for-sale securities:
Cost basis	480	489
Gross unrealized gains	40	240
Gross unrealized losses	(2)	0
Fair Value	518	729
Equity method investments:
Equity method investments	69,466	67,673
Other Investments	0	0
Total investments	69,984	68,402
Results of Investment Liquidation [Abstract]
Proceeds from sale of investments	19	0	16
Gain (loss) on sale of investments	10	0	$ (3)
MGE [Member] | ATC [Member]
Equity method investments:
Equity method investments	69,466	67,673
MGE [Member] | Other Equity Method Investments [Member]
Equity method investments:
Equity method investments	$ 0	$ 0