Investment Securities - (Tables)

3 Months Ended

Mar. 31, 2017

Investments, Debt and Equity Securities [Abstract]

Available-for-sale Securities

At March 31, 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:

	March 31, 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	$	206,779	$	3,798	$	(543)	$	210,034
Other residential MBS issued or guaranteed by U.S. Government agencies or sponsored enterprises		721,536		1,955		(15,282)		708,209
Municipal securities		3,228		—		(9)		3,219
Other securities		419		—		—		419
Total investment securities available-for-sale	$	931,962	$	5,753	$	(15,834)	$	921,881

	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 investment securities available-for-sale	$	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:

	March 31, 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	$	92,828	$	(543)	$	—	$	—	$	92,828	$	(543)
Other residential MBS issued or guaranteed by U.S. Government agencies or sponsored enterprises		200,493		(3,023)		365,901		(12,259)		566,394		(15,282)
Municipal securities		3,058		(9)		—		—		3,058		(9)
Total	$	296,379	$	(3,575)	$	365,901	$	(12,259)	$	662,280	$	(15,834)

	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:

	March 31, 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	$	247,775	$	1,367	$	(202)	$	248,940
Other residential MBS issued or guaranteed by U.S. Government agencies or sponsored enterprises		65,671		7		(1,348)		64,330
Total investment securities held-to-maturity	$	313,446	$	1,374	$	(1,550)	$	313,270

	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:

	March 31, 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	$	23,896	$	(202)	$	—	$	—	$	23,896	$	(202)
Other residential MBS issued or guaranteed by U.S. Government agencies or sponsored enterprises		25,504		(347)		30,768		(1,001)		56,272		(1,348)
Total	$	49,400	$	(549)	$	30,768	$	(1,001)	$	80,168	$	(1,550)

	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)