Investment Securities - (Tables)

12 Months Ended

Dec. 31, 2016

Investments, Debt and Equity Securities [Abstract]

Available-for-sale Securities

Available-for-sale securities are summarized as follows as of the dates indicated:

	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

	December 31, 2015
	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	$	305,773	$	5,721	$	(516)	$	310,978
Other residential MBS issued or guaranteed by U.S. Government agencies or sponsored enterprises		861,321		3,638		(19,416)		845,543
Municipal securities		306		—		—		306
Other securities		419		—		—		419
Total investment securities available-for-sale	$	1,167,819	$	9,359	$	(19,932)	$	1,157,246

Summary of unrealized losses for available-for-sale securities

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

	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)

	December 31, 2015
	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	$	109,182	$	(516)	$	—	$	—	$	109,182	$	(516)
Other residential MBS issued or guaranteed by U.S. Government agencies or sponsored enterprises		67,527		(404)		575,954		(19,012)		643,481		(19,416)
Total	$	176,709	$	(920)	$	575,954	$	(19,012)	$	752,663	$	(19,932)

Held-to-maturity Securities

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

	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

	December 31, 2015
			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	$	340,131	$	2,911	$	(230)	$	342,812
Other residential MBS issued or guaranteed by U.S. Government agencies or sponsored enterprises		87,372		35		(1,634)		85,773
Total investment securities held-to-maturity	$	427,503	$	2,946	$	(1,864)	$	428,585

Summary of unrealized losses for held-to-maturity securities

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

	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)

	December 31, 2015
	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	$	34,641	$	(205)	$	853	$	(25)	$	35,494	$	(230)
Other residential MBS issued or guaranteed by U.S. Government agencies or sponsored enterprises		28,490		(180)		45,872		(1,454)		74,362		(1,634)
Total	$	63,131	$	(385)	$	46,725	$	(1,479)	$	109,856	$	(1,864)