Investments (Real Estate) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Other long-term investments	$ 48,933		$ 53,954
Real Estate
Schedule of Available-for-sale Securities [Line Items]
Other long-term investments	31,300		$ 31,800
Operating income from real estate	$ 2,100	$ 2,000