Investments (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Investments carried at fair value	$ 3,137		$ 2,907
Dividend and interest income from investments	45
Net unrealized gains recognized	$ 187	$ 83