INVESTMENT IN RELATED PARTY INVESTMENT FUND Summarized Income Statements of SILP (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Expenses
Management fee	$ (616)	$ (1,278)	$ (3,131)	$ (8,563)
Interest	(1,562)	(1,562)	(3,123)	(3,106)
Realized and change in unrealized gains (losses)
Net income (loss)	(63)	15,314	(40,333)	21,220
GLRE Limited Partners’ share of net income (loss)	1,609	14,405	(40,517)	45,161
Management fees	616	1,567	1,278	3,582
Performance allocation	0	1,564	0	4,981
Solasglas Investment LP (SILP)
Investment income
Dividend income (net of withholding taxes)	287	442	1,034	1,682
Interest income	17	904	226	1,590
Total Investment income	304	1,346	1,260	3,272
Expenses
Management fee	(616)	(1,568)	(1,278)	(3,582)
Interest	(325)	(845)	(342)	(2,219)
Dividends	(254)	(366)	(399)	(1,436)
Professional fees and other	(124)	(425)	(332)	(805)
Total expenses	(1,319)	(3,204)	(2,351)	(8,042)
Net investment income (loss)	(1,015)	(1,858)	(1,091)	(4,770)
Realized and change in unrealized gains (losses)
Net realized gain (loss)	(31,607)	19,404	(43,560)	12,229
Net change in unrealized appreciation (depreciation)	34,772	1,630	(5,021)	51,383
Net gain (loss) on investment transactions	3,165	21,034	(48,581)	63,612
Net income (loss)	2,150	19,176	(49,672)	58,842
GLRE Limited Partners’ share of net income (loss)	$ 1,609	$ 14,405	$ (40,517)	$ 45,161