CONSOLIDATED STATEMENTS OF CASH FLOWS - (Restricted cash and investments) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Reconciliation of Cash and cash equivalents and restricted cash
Cash and cash equivalents at beginning of period	$ 27,042	$ 4,902	$ 7,015
Restricted cash at beginning of period	1,757	1,731	1,707
Cash and cash equivalents and restricted cash at beginning of period	28,799	6,633	8,722
Cash and cash equivalents at end of period	53,303	27,042	4,902
Restricted cash at end of period	776	1,757	1,731
Cash and cash equivalents and restricted cash at end of period	$ 54,079	$ 28,799	$ 6,633