Consolidated Statements of Operations (Parenthetical) - Partnership Interest [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Interest Income	$ 1,180	$ 1,590	$ 1,210
Trading Securities, Change in Unrealized Holding Gain (Loss)	$ (773)	$ 1,734	$ 1,058