Investments, Unrealized Gains (Losses) on Equity Securities (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Investments [Abstract]
Net realized and unrealized gains (losses) recognized during the period on equity securities	$ 1,355	$ (5,337)	$ (7,100)	$ 2,265
Less: Net realized gains (losses) recognized during the period on equity securities sold during the period	0	0	0	1,113
Unrealized gains (losses) recognized during the reporting period on equity securities, net	$ 1,355	$ (5,337)	$ (7,100)	$ 1,152