Investments Securities

9 Months Ended

Sep. 30, 2020

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 September 30, 2020 and December 31, 2019.

	Gross Unrealized
	(dollars in thousands)
September 30, 2020	Cost		Gains		Losses		Fair Value
Equity	$	259,356	$	160,336	$	(11,785)	$	407,907
Debt	519,421		20,198		(940)		538,679
Other	10,564		—		(6)		10,558
Total	$	789,341	$	180,534	$	(12,731)	$	957,144

	Gross Unrealized
	(dollars in thousands)
December 31, 2019	Cost		Gains		Losses		Fair Value
Equity	$	258,870	$	144,832	$	(5,990)	$	397,712
Debt	354,535		8,474		(874)		362,135
Other	6,356		—		—		6,356
Total	$	619,761	$	153,306	$	(6,864)	$	766,203