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, 2017
U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations	$	1,506,914	$	2,400	$	(22,816	)	$	1,486,498
State and municipal securities	484,376		7,316		(4,337		)	487,355
U.S. government agency and government-sponsored enterprise securities	352,323		1,241		(1,381		)	352,183
U.S. government securities	252		—		—			252
Other securities	5,284		60		(273		)	5,071
Total	$	2,349,149	$	11,017	$	(28,807	)	$	2,331,359
December 31, 2016
U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations	$	1,486,690	$	2,760	$	(23,718	)	$	1,465,732
State and municipal securities	473,914		6,343		(5,197		)	475,060
U.S. government agency and government-sponsored enterprise securities	332,348		1,065		(1,511		)	331,902
U.S. government securities	801		—		(1		)	800
Other securities	5,284		63		(264		)	5,083
Total	$	2,299,037	$	10,231	$	(30,691	)	$	2,278,577

There were no proceeds from sales of securities available for sale for the three months ended March 31, 2017 and there were $38.9 million for the three months ended March 31, 2016. The following table provides the gross realized gains and losses on the sales of securities for the periods indicated:



	Three Months Ended
	March 31,
	2017		2016
	(in thousands)
Gross realized gains	$	—	$	373
Gross realized losses	—		—
Net realized gains	$	—	$	373

The scheduled contractual maturities of investment securities available for sale at March 31, 2017 are presented as follows:



	March 31, 2017
	Amortized Cost		Fair Value
	(in thousands)
Due within one year	$	53,518	$	53,606
Due after one year through five years	502,633		505,398
Due after five years through ten years	731,123		724,361
Due after ten years	1,056,591		1,042,923
Other securities with no stated maturity	5,284		5,071
Total investment securities available-for-sale	$	2,349,149	$	2,331,359

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, 2017
	(in thousands)
Washington and Oregon State to secure public deposits	$	228,794
Federal Reserve Bank to secure borrowings	54,551
Other securities pledged	125,954
Total securities pledged as collateral	$	409,299

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, 2017 and December 31, 2016:



	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, 2017
U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations	$	1,038,971	$	(17,020	)	$	155,846	$	(5,796	)	$	1,194,817	$	(22,816	)
State and municipal securities	162,860		(4,249		)	3,412		(88		)	166,272		(4,337		)
U.S. government agency and government-sponsored enterprise securities	193,846		(1,381		)	—		—			193,846		(1,381		)
U.S. government securities	251		—			—		—			251		—
Other securities	2,263		(51		)	2,734		(222		)	4,997		(273		)
Total	$	1,398,191	$	(22,701	)	$	161,992	$	(6,106	)	$	1,560,183	$	(28,807	)

December 31, 2016
U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations	$	1,029,116	$	(18,788	)	$	159,046	$	(4,930	)	$	1,188,162	$	(23,718	)
State and municipal securities	211,342		(5,064		)	3,384		(133		)	214,726		(5,197		)
U.S. government agency and government-sponsored enterprise securities	218,811		(1,511		)	—		—			218,811		(1,511		)
U.S. government securities	251		(1		)	—		—			251		(1		)
Other securities	2,263		(51		)	2,743		(213		)	5,006		(264		)
Total	$	1,461,783	$	(25,415	)	$	165,173	$	(5,276	)	$	1,626,956	$	(30,691	)

At March 31, 2017, there were 198 U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations securities in an unrealized loss position, of which 52 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, 2017.

At March 31, 2017, there were 142 state and municipal government securities in an unrealized loss position, of which five 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, 2017, 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, 2017.

At March 31, 2017, there were 20 U.S. government agency and government-sponsored enterprise securities in an unrealized loss position, of which none 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, 2017.

At March 31, 2017, there was one U.S. government security in an unrealized loss position, which was not 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 this investment falls within the yield curve and its individual characteristics. Because the Company does not currently intend to sell this security nor does the Company consider it more likely than not that it will be required to sell this security before the recovery of amortized cost basis, which may be upon maturity, the Company does not consider this investment to be other-than-temporarily impaired at March 31, 2017.

At March 31, 2017, there were two other securities in an unrealized loss position, of which one 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 these investments to be other-than-temporarily impaired at March 31, 2017 as it has the intent and ability to hold this investment for sufficient time to allow for recovery in the market value.