Investment Securities - (Tables)

12 Months Ended

Dec. 31, 2015

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, 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
Other securities		725		—		—		725
Total	$	1,167,819	$	9,359	$	(19,932)	$	1,157,246

	December 31, 2014
	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	$	395,244	$	9,014	$	(43)	$	404,215
Other residential MBS issued or guaranteed by U.S. Government agencies or sponsored enterprises		1,088,834		7,464		(21,718)		1,074,580
Other securities		419		—		—		419
Total	$	1,484,497	$	16,478	$	(21,761)	$	1,479,214

Summary of Unrealized Losses

The table below summarizes the unrealized losses as of the dates shown, along with the length of the impairment period:

	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)

	December 31, 2014
	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	$	17	$	—	$	89,749	$	(43)	$	89,766	$	(43)
Other residential MBS issued or guaranteed by U.S. Government agencies or sponsored enterprises		88,854		(2,053)		667,368		(19,665)		756,222		(21,718)
Total	$	88,871	$	(2,053)	$	757,117	$	(19,708)	$	845,988	$	(21,761)

Held-to-maturity Securities

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

	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

	December 31, 2014
			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	$	422,622	$	5,773	$	(72)	$	428,323
Other residential MBS issued or guaranteed by U.S. Government agencies or sponsored enterprises		107,968		217		(1,871)		106,314
Total investment securities held-to-maturity	$	530,590	$	5,990	$	(1,943)	$	534,637

Held-to-maturity securities continuous unrealized loss position fair value [Table Text Block]

The table below summarizes the unrealized losses as of the dates shown, along with the length of the impairment period:

	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)

	December 31, 2014
	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	$	—	$	—	$	35,139	$	(72)	$	35,139	$	(72)
Other residential MBS issued or guaranteed by U.S. Government agencies or sponsored enterprises		—		—		75,139		(1,871)		75,139		(1,871)
Total	$	—	$	—	$	110,278	$	(1,943)	$	110,278	$	(1,943)