Summary of Significant Accounting Principles (Details-1) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Cash Cash Equivalents And Restricted Cash [Line Items]
Cash and cash equivalents	$ 17,451	$ 23,481
Restricted cash	473	619
Receivable - margin account	1,870	1,714
Cash, cash equivalents, and restricted cash	19,794	25,814	$ 84,416	$ 84,929
MGE [Member]
Cash Cash Equivalents And Restricted Cash [Line Items]
Cash and cash equivalents	3,321	3,196
Restricted cash	473	619
Receivable - margin account	1,870	1,714
Cash, cash equivalents, and restricted cash	$ 5,664	$ 5,529	$ 11,638	$ 6,670