Investments (Tables)

12 Months Ended

Dec. 31, 2019

Schedule of Investments [Abstract]

Summary of debt and equity securities

The following tables summarize debt and equity securities at December 31, 2019 and 2018.

	(dollars in thousands)
	Gross Unrealized
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

	(dollars in thousands)
	Gross Unrealized
2018	Cost		Gains		Losses		Fair Value
Equity	$	251,226	$	64,954	$	(9,105)	$	307,075
Debt	278,030		1,718		(4,955)		274,793
Other	3,075		—		—		3,075
Total	$	532,331	$	66,672	$	(14,060)	$	584,943

Schedule of contractual maturities of debt securities

The contractual maturities of debt securities, which are included in the estimated fair value table above, at December 31, 2019 and 2018 are as follows:

	(dollars in thousands)
	2019				2018
	Cost		Fair Value		Cost		Fair Value
Due within one year	$	81,637	$	81,914	$	65,039	$	63,925
Due after one year through five years	47,212		48,188		62,293		61,924
Due after five years through ten years	51,892		54,184		50,606		49,855
Due after ten years	173,794		177,849		100,092		99,089
Total	$	354,535	$	362,135	$	278,030	$	274,793

Summary of realized gains and losses and proceeds from sales of securities

The following table summarizes the realized gains and losses and proceeds from sales of securities for the years ended December 31, 2019, 2018 and 2017:

	(dollars in thousands)
	2019		2018		2017
Gross realized gains	$	18,076	$	14,268	$	35,523
Gross realized losses	(12,018)		(19,139)		(16,909)
Proceeds from sales	544,043		626,612		521,345

Schedule of investments in associated companies

Investments in associated companies were as follows at December 31, 2019 and 2018:

	(dollars in thousands)
	2019		2018
National Rural Utilities Cooperative Finance Corporation (CFC)	$	24,065	$	24,061
CT Parts, LLC	7,175		10,236
Georgia Transmission Corporation	32,106		30,237
Georgia System Operations
Corporation	7,000		9,250
Other	2,972		3,253
Total	$	73,318	$	77,037