Investments Securities

3 Months Ended

Mar. 31, 2021

Investments, Debt and Equity Securities [Abstract]

Investment Securities

Investment Securities.    Investment securities we hold are recorded at fair value in the accompanying consolidated balance sheets. We apply regulated operations accounting to the unrealized gains and losses of all investment securities. All realized and unrealized gains and losses are determined using the specific identification method.

The following tables summarize debt and equity securities as of March 31, 2021 and December 31, 2020.

	Gross Unrealized
	(dollars in thousands)
March 31, 2021	Cost		Gains		Losses		Fair Value
Equity	$	257,064	$	229,874	$	(5,207)	$	481,731
Debt	668,068		8,379		(5,512)		670,935
Other	21,775		—		(32)		21,743
Total	$	946,907	$	238,253	$	(10,751)	$	1,174,409

	Gross Unrealized
	(dollars in thousands)
December 31, 2020	Cost		Gains		Losses		Fair Value
Equity	$	262,564	$	219,658	$	(8,127)	$	474,095
Debt	613,271		18,090		(641)		630,720
Other	11,431		—		—		11,431
Total	$	887,266	$	237,748	$	(8,768)	$	1,116,246