Securities

The following table summarizes the amortized cost, gross unrealized gains and losses and the resulting fair value of securities available for sale:



	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(in thousands)
March 31, 2015
U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations	$	1,093,576	$	13,765	$	(4,641	)	$	1,102,700
State and municipal securities	486,969		15,434		(732		)	501,671
U.S. government agency and government-sponsored enterprise securities	375,230		2,551		(983		)	376,798
U.S. government securities	20,918		—		(140		)	20,778
Other securities	5,284		40		(112		)	5,212
Total	$	1,981,977	$	31,790	$	(6,608	)	$	2,007,159
December 31, 2014
U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations	$	1,160,378	$	10,219	$	(8,210	)	$	1,162,387
State and municipal securities	483,578		14,432		(1,526		)	496,484
U.S. government agency and government-sponsored enterprise securities	416,919		856		(4,069		)	413,706
U.S. government securities	20,910		—		(411		)	20,499
Other securities	5,284		20		(123		)	5,181
Total	$	2,087,069	$	25,527	$	(14,339	)	$	2,098,257

Proceeds from sales of securities available-for-sale were $57.2 million and $6.4 million for the three months ended March 31, 2015 and 2014, respectively. The following table provides the gross realized gains and losses on the sales of securities for the periods indicated:



	Three Months Ended
	March 31,
	2015			2014
	(in thousands)
Gross realized gains	$	730		$	223
Gross realized losses	(9		)	—
Net realized gains	$	721		$	223

The scheduled contractual maturities of investment securities available for sale at March 31, 2015 are presented as follows:



	March 31, 2015
	Amortized Cost		Fair Value
	(in thousands)
Due within one year	$	15,480	$	15,601
Due after one year through five years	404,752		406,989
Due after five years through ten years	526,230		534,584
Due after ten years	1,030,231		1,044,773
Other securities with no stated maturity	5,284		5,212
Total investment securities available-for-sale	$	1,981,977	$	2,007,159

The following table summarizes the carrying value of securities pledged as collateral to secure public deposits, borrowings and other purposes as permitted or required by law:



	March 31, 2015
	(in thousands)
Washington and Oregon State to secure public deposits	$	323,771
Federal Reserve Bank to secure borrowings	36,945
Other securities pledged	156,385
Total securities pledged as collateral	$	517,101

The following table shows the gross unrealized losses and fair value of the Company’s investments with unrealized losses that are not deemed to be other-than-temporarily impaired, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position at March 31, 2015 and December 31, 2014:



	Less than 12 Months					12 Months or More					Total
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
	(in thousands)
March 31, 2015
U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations	$	94,304	$	(634	)	$	213,050	$	(4,007	)	$	307,354	$	(4,641	)
State and municipal securities	45,809		(227		)	31,597		(505		)	77,406		(732		)
U.S. government agency and government-sponsored enterprise securities	999		(1		)	178,013		(982		)	179,012		(983		)
U.S. government securities	1,050		(1		)	19,728		(139		)	20,778		(140		)
Other securities	—		—			2,843		(112		)	2,843		(112		)
Total	$	142,162	$	(863	)	$	445,231	$	(5,745	)	$	587,393	$	(6,608	)

December 31, 2014
U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations	$	258,825	$	(1,287	)	$	279,015	$	(6,924	)	$	537,840	$	(8,211	)
State and municipal securities	71,026		(543		)	44,148		(982		)	115,174		(1,525		)
U.S. government agency and government-sponsored enterprise securities	105,250		(518		)	216,221		(3,551		)	321,471		(4,069		)
U.S. government securities	—		—			19,450		(411		)	19,450		(411		)
Other securities	2,313		(2		)	2,834		(121		)	5,147		(123		)
Total	$	437,414	$	(2,350	)	$	561,668	$	(11,989	)	$	999,082	$	(14,339	)

At March 31, 2015, there were 77 U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations securities in an unrealized loss position, of which 34 were in a continuous loss position for 12 months or more. The decline in fair value is attributable to changes in interest rates relative to where these investments fall within the yield curve and their individual characteristics. Because the Company does not intend to sell these securities nor does the Company consider it more likely than not that it will be required to sell these securities before the recovery of amortized cost basis, which may be upon maturity, the Company does not consider these investments to be other-than-temporarily impaired at March 31, 2015.

At March 31, 2015, there were 66 state and municipal government securities in an unrealized loss position, of which 32 were in a continuous loss position for 12 months or more. The unrealized losses on state and municipal securities were caused by interest rate changes or widening of market spreads subsequent to the purchase of the individual securities. Management monitors published credit ratings of these securities for adverse changes. As of March 31, 2015, none of the rated obligations of state and local government entities held by the Company had a below investment grade credit rating. Because the credit quality of these securities are investment grade and the Company does not intend to sell these securities nor does the Company consider it more likely than not that it will be required to sell these securities before the recovery of amortized cost basis, which may be upon maturity, the Company does not consider these investments to be other-than-temporarily impaired at March 31, 2015.

At March 31, 2015, there were 18 U.S. government agency and government-sponsored enterprise securities in an unrealized loss position, 14 of which were in a continuous loss position for 12 months or more. The decline in fair value is attributable to changes in interest rates relative to where these investments fall within the yield curve and their individual characteristics. Because the Company does not currently intend to sell these securities nor does the Company consider it more likely than not that it will be required to sell these securities before the recovery of amortized cost basis, which may be upon maturity, the Company does not consider these investments to be other-than-temporarily impaired at March 31, 2015.

At March 31, 2015, there were four U.S. government securities in an unrealized loss position, two of which were in a continuous loss position for 12 months or more. The decline in fair value is attributable to changes in interest rates relative to where these investments fall within the yield curve and their individual characteristics. Because the Company does not currently intend to sell these securities nor does the Company consider it more likely than not that it will be required to sell these securities before the recovery of amortized cost basis, which may be upon maturity, the Company does not consider these investments to be other-than-temporarily impaired at March 31, 2015.

At March 31, 2015, there was one other security in an unrealized loss position, which was in a continuous unrealized loss position for 12 months or more. The decline in fair value is attributable to changes in interest rates and the additional risk premium investors are demanding for investment securities with these characteristics. The Company does not consider this investment to be other-than-temporarily impaired at March 31, 2015 as it has the intent and ability to hold the investment for sufficient time to allow for recovery in the market value.