Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost, Current	$ 5,110	$ 5,914
Municipal Bonds [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost, Current	5,110	5,914
Amortized Cost, Due from one through five years	12,408	14,398
Amortized Cost, Due from six through ten years	7,937	9,337
Amortized Cost, Due from eleven through twenty years	1,398	805
Amortized Cost, Total	26,853	30,454
Market Value, Current	5,684	6,006
Market Value, Due from one through five years	12,539	15,204
Market Value, Due from six through ten years	8,163	9,711
Market Value, Due from eleven through twenty years	1,343	762
Market Value, Total	$ 27,729	$ 31,683