Investment Securities

Securities Available-for-Sale

The following table presents amortized cost, gross unrealized gains and losses, and carrying values of securities available-for-sale as of the dates indicated:



	March 31, 2016									December 31, 2015
			Gross		Gross							Gross		Gross
	Amortized		Unrealized		Unrealized			Fair		Amortized		Unrealized		Unrealized			Fair
Security Type:	Cost		Gains		Losses			Value		Cost		Gains		Losses			Value
	(In thousands)
Residential mortgage-backed securities:
Government agency and
government-sponsored enterprise
pass-through securities	$	642,233	$	12,865	$	(1,233	)	$	653,865	$	759,881	$	12,075	$	(4,159	)	$	767,797
Government agency and
government-sponsored enterprise
collateralized mortgage obligations	431,456		12,515		(239		)	443,732		486,065		3,584		(3,410		)	486,239
Covered private label collateralized
mortgage obligations	23,026		5,064		(227		)	27,863		24,113		5,794		(125		)	29,782
Other private label collateralized
mortgage obligations	108,019		246		(883		)	107,382		115,952		43		(981		)	115,014
Municipal securities	1,457,795		59,886		(89		)	1,517,592		1,508,968		39,435		(1,072		)	1,547,331
US Treasury securities	—		—		—			—		70,196		—		(816		)	69,380
Corporate debt securities	47,269		303		(2,089		)	45,483		49,047		327		(950		)	48,424
Collateralized loan obligations	142,637		42		(3,107		)	139,572		133,192		128		(1,131		)	132,189
SBA securities	201,934		947		(207		)	202,674		211,946		41		(830		)	211,157
Government-sponsored enterprise debt
securities	—		—		—			—		36,302		611		—			36,913
Asset-backed and other securities	104,182		135		(1,894		)	102,423		116,723		119		(1,631		)	115,211
Total	$	3,158,551	$	92,003	$	(9,968	)	$	3,240,586	$	3,512,385	$	62,157	$	(15,105	)	$	3,559,437

As of March 31, 2016, securities available‑for‑sale with a carrying value of $414.6 million were pledged as collateral for borrowings, public deposits and other purposes as required by various statutes and agreements.

During the three months ended March 31, 2016 and 2015, we purchased $52.2 million and $196.6 million in securities available-for-sale.

During the three months ended March 31, 2016, we sold $334.9 million of various securities, primarily government agency and government-sponsored enterprise ("GSE") pass-through securities and collateralized mortgage obligations, U.S. Treasury securities and GSE debt securities, for a gross realized gain of $8.9 million and a gross realized loss of $0.8 million. During the three months ended March 31, 2015, we sold $141.7 million of various securities, primarily corporate debt securities and GSE pass-through securities, for a gross realized gain of $3.7 million and a gross realized loss of $0.4 million.

Unrealized Losses on Securities Available-for-Sale

The following tables present the gross unrealized losses and fair values of securities available-for-sale that were in unrealized loss positions, for which other-than-temporary impairments have not been recognized in earnings, as of the dates indicated:



	March 31, 2016
	Less Than 12 Months					12 Months or More					Total
			Gross					Gross					Gross
	Fair		Unrealized			Fair		Unrealized			Fair		Unrealized
Security Type:	Value		Losses			Value		Losses			Value		Losses
	(In thousands)
Residential mortgage-backed securities:
Government agency and government-
sponsored enterprise pass-through
securities	$	196,388	$	(1,135	)	$	9,422	$	(98	)	$	205,810	$	(1,233	)
Government agency and government-
sponsored enterprise collateralized
mortgage obligations	33,702		(239		)	—		—			33,702		(239		)
Covered private label collateralized
mortgage obligations	1,239		(98		)	849		(129		)	2,088		(227		)
Other private label collateralized
mortgage obligations	59,407		(838		)	1,029		(45		)	60,436		(883		)
Municipal securities	18,108		(55		)	5,496		(34		)	23,604		(89		)
Corporate debt securities	28,180		(2,089		)	—		—			28,180		(2,089		)
Collateralized loan obligations	106,773		(2,121		)	23,355		(986		)	130,128		(3,107		)
SBA securities	87,150		(207		)	—		—			87,150		(207		)
Asset-backed and other securities	64,013		(1,285		)	15,923		(609		)	79,936		(1,894		)
Total	$	594,960	$	(8,067	)	$	56,074	$	(1,901	)	$	651,034	$	(9,968	)



	December 31, 2015
	Less Than 12 Months					12 Months or More					Total
			Gross					Gross					Gross
	Fair		Unrealized			Fair		Unrealized			Fair		Unrealized
Security Type:	Value		Losses			Value		Losses			Value		Losses
	(In thousands)
Residential mortgage-backed securities:
Government agency and government-
sponsored enterprise pass-through
securities	$	391,642	$	(3,893	)	$	9,342	$	(266	)	$	400,984	$	(4,159	)
Government agency and government-
sponsored enterprise collateralized
mortgage obligations	314,284		(2,769		)	14,230		(641		)	328,514		(3,410		)
Covered private label collateralized
mortgage obligations	1,354		(57		)	568		(68		)	1,922		(125		)
Other private label collateralized
mortgage obligations	92,179		(943		)	1,070		(38		)	93,249		(981		)
Municipal securities	126,892		(1,061		)	531		(11		)	127,423		(1,072		)
US Treasury securities	69,380		(816		)	—		—			69,380		(816		)
Corporate debt securities	29,379		(950		)	—		—			29,379		(950		)
Collateralized loan obligations	100,993		(1,131		)	—		—			100,993		(1,131		)
SBA securities	179,942		(830		)	—		—			179,942		(830		)
Asset-backed and other securities	71,619		(1,182		)	16,091		(449		)	87,710		(1,631		)
Total	$	1,377,664	$	(13,632	)	$	41,832	$	(1,473	)	$	1,419,496	$	(15,105	)

We reviewed the securities that were in a loss position at March 31, 2016, and concluded their unrealized losses were not a result of downgraded credit ratings or other indicators of deterioration of the underlying issuers' ability to repay. Such unrealized losses were a result of the level of market interest rates and pricing changes caused by shifting supply and demand dynamics relative to the types of securities. Accordingly, we determined the securities were temporarily impaired and we did not recognize such impairment in the condensed consolidated statements of earnings. Although we occasionally sell securities for portfolio management purposes, we do not foresee having to sell any temporarily impaired securities strictly for liquidity needs and believe that it is more likely than not we would not be required to sell any temporarily impaired securities before recovery of their amortized cost.

Contractual Maturities of Securities Available-for-Sale

The following table presents the contractual maturities of our available-for-sale securities portfolio based on amortized cost and carrying value as of the date indicated:



	March 31, 2016
	Amortized		Fair
Maturity:	Cost		Value
	(In thousands)
Due in one year or less	$	12,821	$	12,628
Due after one year through five years	216,420		219,110
Due after five years through ten years	603,523		619,214
Due after ten years	2,325,787		2,389,634
Total securities available-for-sale	$	3,158,551	$	3,240,586

Mortgage-backed securities have contractual terms to maturity, but require periodic payments to reduce principal. In addition, expected maturities may differ from contractual maturities because obligors and/or issuers may have the right to call or prepay obligations with or without call or prepayment penalties.

Interest Income on Investment Securities

The following table presents the composition of our interest income on investment securities for the periods indicated:



	Three Months Ended
	March 31,		December 31,		March 31,
	2016		2015		2015
	(In thousands)
Taxable interest	$	11,396	$	12,730	$	7,473
Non-taxable interest	10,726		10,459		3,894
Dividend income	425		459		828
Total interest income on investment securities	$	22,547	$	23,648	$	12,195