Investment in Marketable Securities (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2015	Dec. 31, 2016
Investment in Marketable Securities (Textual) [Abstract]
Investment in marketable securities	$ 110,629,000			$ 183,883,000
Impairment on securities included as a component of realized gain (loss)	87,156,000			125,311,000
Net accumulated other comprehensive income	23,473,000		$ 58,572,000
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax	47,000			598,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	3,265,000			$ 1,204,000
Impairments on available for sale securities	0	$ 0
Dividend Income, Operating	$ 1,843,000	$ 2,655,000