Investment Securities - (Tables)

6 Months Ended

Jun. 30, 2017

Investments, Debt and Equity Securities [Abstract]

Available-for-sale Securities

At June 30, 2017 and December 31, 2016, the Company held $0.9 billion of available-for-sale investment securities. Available-for-sale securities are summarized as follows as of the dates indicated:

	June 30, 2017
	Amortized		Gross		Gross
	cost		unrealized gains		unrealized losses		Fair value
Mortgage-backed securities (“MBS”):
Residential mortgage pass-through securities issued or guaranteed by U.S. Government agencies or sponsored enterprises	$	192,369	$	3,476	$	(504)	$	195,341
Other residential MBS issued or guaranteed by U.S. Government agencies or sponsored enterprises		680,040		1,604		(13,013)		668,631
Municipal securities		2,323		—		—		2,323
Other securities		419		—		—		419
Total	$	875,151	$	5,080	$	(13,517)	$	866,714

	December 31, 2016
	Amortized		Gross		Gross
	cost		unrealized gains		unrealized losses		Fair value
Mortgage-backed securities (“MBS”):
Residential mortgage pass-through securities issued or guaranteed by U.S. Government agencies or sponsored enterprises	$	223,781	$	3,909	$	(530)	$	227,160
Other residential MBS issued or guaranteed by U.S. Government agencies or sponsored enterprises		666,616		2,124		(16,001)		652,739
Municipal securities		3,921		—		(7)		3,914
Other securities		419		—		—		419
Total	$	894,737	$	6,033	$	(16,538)	$	884,232

Summary of unrealized losses for available-for-sale securities

The table below summarizes the available-for-sale securities with unrealized losses as of the dates shown, along with the length of the impairment period:

	June 30, 2017
	Less than 12 months				12 months or more				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	value		losses		value		losses		value		losses
Mortgage-backed securities (“MBS”):
Residential mortgage pass-through securities issued or guaranteed by U.S. Government agencies or sponsored enterprises	$	79,548	$	(504)	$	—	$	—	$	79,548	$	(504)
Other residential MBS issued or guaranteed by U.S. Government agencies or sponsored enterprises		148,819		(2,279)		354,843		(10,734)		503,662		(13,013)
Total	$	228,367	$	(2,783)	$	354,843	$	(10,734)	$	583,210	$	(13,517)

	December 31, 2016
	Less than 12 months				12 months or more				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	value		losses		value		losses		value		losses
Mortgage-backed securities (“MBS”):
Residential mortgage pass-through securities issued or guaranteed by U.S. Government agencies or sponsored enterprises	$	100,898	$	(530)	$	—	$	—	$	100,898	$	(530)
Other residential MBS issued or guaranteed by U.S. Government agencies or sponsored enterprises		137,576		(2,976)		385,707		(13,025)		523,283		(16,001)
Municipal securities		3,058		(7)		—		—		3,058		(7)
Total	$	241,532	$	(3,513)	$	385,707	$	(13,025)	$	627,239	$	(16,538)

Held-to-maturity Securities

Held-to-maturity investment securities are summarized as follows as of the dates indicated:

	June 30, 2017
			Gross		Gross
	Amortized		unrealized		unrealized
	cost		gains		losses		Fair value
Mortgage-backed securities (“MBS”):
Residential mortgage pass-through securities issued or guaranteed by U.S. Government agencies or sponsored enterprises	$	233,026	$	1,332	$	(164)	$	234,194
Other residential MBS issued or guaranteed by U.S. Government agencies or sponsored enterprises		61,865		11		(1,201)		60,675
Total investment securities held-to-maturity	$	294,891	$	1,343	$	(1,365)	$	294,869

	December 31, 2016
			Gross		Gross
	Amortized		unrealized		unrealized
	cost		gains		losses		Fair value
Mortgage-backed securities (“MBS”):
Residential mortgage pass-through securities issued or guaranteed by U.S. Government agencies or sponsored enterprises	$	263,411	$	1,685	$	(234)	$	264,862
Other residential MBS issued or guaranteed by U.S. Government agencies or sponsored enterprises		69,094		16		(1,399)		67,711
Total investment securities held-to-maturity	$	332,505	$	1,701	$	(1,633)	$	332,573

Summary of unrealized losses for held-to-maturity securities

The table below summarizes the held-to-maturity securities with unrealized losses as of the dates shown, along with the length of the impairment period:

	June 30, 2017
	Less than 12 months				12 months or more				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	value		losses		value		losses		value		losses
Mortgage-backed securities (“MBS”):
Residential mortgage pass-through securities issued or guaranteed by U.S. Government agencies or sponsored enterprises	$	25,512	$	(164)	$	—	$	—	$	25,512	$	(164)
Other residential MBS issued or guaranteed by U.S. Government agencies or sponsored enterprises		23,861		(306)		29,244		(895)		53,105		(1,201)
Total	$	49,373	$	(470)	$	29,244	$	(895)	$	78,617	$	(1,365)

	December 31, 2016
	Less than 12 months				12 months or more				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	value		losses		value		losses		value		losses
Mortgage-backed securities (“MBS”):
Residential mortgage pass-through securities issued or guaranteed by U.S. Government agencies or sponsored enterprises	$	27,799	$	(234)	$	—	$	—	$	27,799	$	(234)
Other residential MBS issued or guaranteed by U.S. Government agencies or sponsored enterprises		26,992		(357)		32,146		(1,042)		59,138		(1,399)
Total	$	54,791	$	(591)	$	32,146	$	(1,042)	$	86,937	$	(1,633)