Organization and Basis of Presentation - Summary of Financial Securities (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Equity securities:
Gross Unrealized Gain (Loss)	$ (8,696)	$ 4,510
Carrying Value	3,200		$ 3,600
Held to maturity
Equity and Debt Securities, Amortized Cost	153,596		140,649
Equity and Debt Securities, Gross Unrealized Gain (Loss)	(5,457)		3,544
Equity and Debt Securities, Marketable Securities	148,139		144,193
Equity and Debt Securities, Allowance for Credit Loss	13,644		0
Investment funds - debt securities
Equity securities:
Amortized Cost/Cost	29,685		29,588
Gross Unrealized Gain (Loss)	(676)		544
Carrying Value	29,009		30,132
Common stock and stock funds
Equity securities:
Amortized Cost/Cost	45,395		34,941
Gross Unrealized Gain (Loss)	(4,549)		2,927
Carrying Value	40,846		37,868
U.S. treasury securities
Available for sale
Amortized Cost/Cost	2,421		2,421
Gross Unrealized Gain (Loss)	16		13
Carrying Value	2,437		2,434
Allowance for Credit Losses	0
Investment-grade unsecured debt
Available for sale
Amortized Cost/Cost	1,050		1,048
Gross Unrealized Gain (Loss)	(248)		60
Carrying Value	802		1,108
Allowance for Credit Losses	0
Mortgage backed securities
Held to maturity
Amortized Cost/Cost	75,045		72,651
Gross Unrealized Gain (Loss)	0		0
Carrying Value	75,045		$ 72,651
Allowance for Credit Losses	$ 13,644

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