SCHEDULE I - CONDENSED FINANCIAL INFORMATION (Details 3) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net cash provided by operating activities	$ 3,012	$ 35,389	$ 30,484
Cash flows from investing activities:
Net cash provided by investing activities	(5,751)	(36,950)	(6,528)
Cash flows from financing activities:
Repurchase of stock for treasury	0	0	(1,488)
Payment of withholding taxes related to stock-based compensation to employees	0	0	(331)
Payment of Dow liabilities settlement	(10,000)	(10,000)	0
Net cash used in financing activities	(22,228)	(14,015)	(6,069)
Net (decrease) increase in cash and cash equivalents	(29,681)	(12,779)	19,547
Cash and cash equivalents, beginning of period	64,533	77,312	57,765
Cash and cash equivalents, end of period	34,852	64,533	77,312
Parent Company
Cash flows from operating activities:
Net cash provided by operating activities	10,000	10,000	1,818
Cash flows from investing activities:
Net cash provided by investing activities	0	0	0
Cash flows from financing activities:
Repurchase of stock for treasury	0	0	(1,487)
Payment of withholding taxes related to stock-based compensation to employees	0	0	(331)
Payment of Dow liabilities settlement	(10,000)	(10,000)	0
Net cash used in financing activities	(10,000)	(10,000)	(1,818)
Net (decrease) increase in cash and cash equivalents	0	0	0
Cash and cash equivalents, beginning of period	0	0	0
Cash and cash equivalents, end of period	$ 0	$ 0	$ 0