Investments (Tables)

12 Months Ended

Dec. 31, 2019

Investments [Abstract]

Schedule of Fair Value of Fixed Maturity Investments Trading

The following table summarizes the fair value of fixed maturity investments trading:

	December 31, 2019		December 31, 2018
U.S. treasuries	$	4,467,345	$	3,331,411
Agencies	343,031		174,883
Municipal	—		6,854
Non-U.S. government	497,392		279,818
Non-U.S. government-backed corporate	321,356		160,063
Corporate	3,075,660		2,450,244
Agency mortgage-backed	1,148,499		817,880
Non-agency mortgage-backed	294,604		278,680
Commercial mortgage-backed	468,698		282,294
Asset-backed	555,070		306,743
Total fixed maturity investments trading	$	11,171,655	$	8,088,870

The following table summarizes the fair value of equity investments trading:

	December 31, 2019		December 31, 2018
Financials	$	248,189	$	200,357
Communications and technology	79,206		42,333
Industrial, utilities and energy	38,583		24,520
Consumer	35,987		20,639
Healthcare	29,510		18,925
Basic materials	5,456		3,478
Total	$	436,931	$	310,252

Schedule of Contractual Maturities of Fixed Maturity Investments

Contractual maturities of fixed maturity investments trading are described in the following table. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.

At December 31, 2019	Amortized  Cost		Fair Value
Due in less than one year	$	543,687	$	544,636
Due after one through five years	5,467,501		5,522,769
Due after five through ten years	2,386,467		2,420,602
Due after ten years	211,424		216,777
Mortgage-backed	1,902,365		1,911,801
Asset-backed	555,970		555,070
Total	$	11,067,414	$	11,171,655

Schedule of Net Investment Income

The components of net investment income are as follows:

Year ended December 31,	2019			2018			2017
Fixed maturity investments	$	318,503		$	211,973		$	179,624
Short term investments	56,264			33,571			11,082
Equity investments	4,808			4,474			3,628
Other investments
Private equity investments	14,981			477			33,999
Other	39,246			22,475			8,067
Cash and cash equivalents	7,676			3,810			1,196
	441,478			276,780			237,596
Investment expenses	(17,645		)	(14,914		)	(15,387		)
Net investment income	$	423,833		$	261,866		$	222,209

Schedule of Net Realized and Unrealized Gains (Losses) On Investments and Net Other-Than-Temporary Impairments

Net realized and unrealized gains (losses) on investments are as follows:

Year ended December 31,	2019			2018			2017
Gross realized gains	$	133,409		$	21,284		$	49,121
Gross realized losses	(43,149		)	(91,098		)	(38,832		)
Net realized gains (losses) on fixed maturity investments	90,260			(69,814		)	10,289
Net unrealized gains (losses) on fixed maturity investments trading	170,183			(57,310		)	8,479
Net realized and unrealized gains (losses) on investments-related derivatives	58,891			(8,784		)	(2,490		)
Net realized gains on equity investments trading sold during the period	31,062			27,739			80,027
Net unrealized gains (losses) on equity investments trading still held at reporting date	64,087			(66,900		)	39,517
Net realized and unrealized gains (losses) on equity investments trading	95,149			(39,161		)	119,544
Net realized and unrealized gains (losses) on investments	$	414,483		$	(175,069	)	$	135,822

Schedule of Other Investments

The table below shows the fair value of the Company’s portfolio of other investments:

At December 31,	2019		2018
Catastrophe bonds	$	781,641	$	516,571
Private equity investments	271,047		242,647
Senior secured bank loan funds	22,598		14,482
Hedge funds	12,091		11,233
Total other investments	$	1,087,377	$	784,933

Schedule of Equity Method Investments

The table below shows the Company’s portfolio of investments in other ventures, under equity method:

	2019				2018
At December 31,	Ownership %		Carrying  Value		Ownership %		Carrying  Value
Tower Hill Companies	24.9	%	36,779		24.9	%	38,241
Top Layer Re	50.0	%	35,363		50.0	%	46,562
Other	26.6	%	34,407		30.6	%	30,369
Total investments in other ventures, under equity method			$	106,549			$	115,172

Schedule of Equity In Earnings of Equity Method Investments

The table below shows the Company’s equity in earnings of other ventures, under equity method:

Year ended December 31,	2019		2018		2017
Tower Hill Companies	$	10,337	$	9,605	$	(1,647	)
Top Layer Re	8,801		8,852		9,851
Other	4,086		17		(174		)
Total equity in earnings of other ventures	$	23,224	$	18,474	$	8,030