Mortgage-Backed Securities (Tables)

6 Months Ended

Jun. 30, 2019

Mortgage Backed Securities [Abstract]

Schedule of Investment in Mortgage Backed Securities Activity

Following is a summary of activity in the Company’s investment in MBS:

	Quarter ended June 30,						Six months ended June 30,
	2019			2018			2019			2018
	(in thousands)
Balance at beginning of period	$	2,589,106		$	1,436,456		$	2,610,422		$	989,461
Purchases		81,202			314,219			81,202			814,792
Repayment		(91,186	)		(42,538	)		(144,868	)		(73,279	)
Changes in fair value included in income arising from:
Amortization of premiums		(6,213	)		(954	)		(10,769	)		(1,394	)
Valuation adjustments		27,448			(8,861	)		64,370			(31,258	)
		21,235			(9,815	)		53,601			(32,652	)
Balance at end of period	$	2,600,357		$	1,698,322		$	2,600,357		$	1,698,322

Schedule of Investment in Mortgage Backed Securities

Following is a summary of the Company’s investment in MBS:

	June 30, 2019								December 31, 2018
Agency: (1)	Principal balance		Unamortized purchase premiums		Accumulated valuation changes		Fair value		Principal balance		Unamortized purchase premiums		Accumulated valuation changes			Fair value
	(in thousands)
Fannie Mae	$	2,012,752	$	31,552	$	36,902	$	2,081,206	$	2,050,769	$	39,488	$	(14,920	)	$	2,075,337
Freddie Mac		503,702		5,252		10,197		519,151		530,734		6,702		(2,351	)		535,085
	$	2,516,454	$	36,804	$	47,099	$	2,600,357	$	2,581,503	$	46,190	$	(17,271	)	$	2,610,422

(1) All MBS are fixed-rate pass-through securities with maturities of more than ten years and are pledged to secure Assets sold under agreements to repurchase at both June 30, 2019 and December 31, 2018.