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)
September 30, 2017
U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations	$	1,391,636	$	3,143	$	(17,362	)	$	1,377,417
State and municipal securities	476,702		9,047		(2,261		)	483,488
U.S. government agency and government-sponsored enterprise securities	341,462		1,372		(1,230		)	341,604
U.S. government securities	251		—		(1		)	250
Other securities	5,284		82		(252		)	5,114
Total	$	2,215,335	$	13,644	$	(21,106	)	$	2,207,873
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

The following table provides the proceeds and gross realized gains and losses on the sales of securities for the periods indicated:



	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2017		2016		2017		2016
	(in thousands)
Proceeds from sales of available for sale securities	$	—	$	37,390	$	—	$	120,800

Gross realized gains	$	—	$	572	$	—	$	1,174
Gross realized losses	—		—		—		—
Net realized gains	$	—	$	572	$	—	$	1,174

The scheduled contractual maturities of investment securities available for sale at September 30, 2017 are presented as follows:



	September 30, 2017
	Amortized Cost		Fair Value
	(in thousands)
Due within one year	$	108,477	$	108,462
Due after one year through five years	506,439		509,784
Due after five years through ten years	672,288		671,188
Due after ten years	922,847		913,325
Other securities with no stated maturity	5,284		5,114
Total investment securities available-for-sale	$	2,215,335	$	2,207,873

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:



	September 30, 2017
	(in thousands)
Washington and Oregon State to secure public deposits	$	242,188
Federal Reserve Bank to secure borrowings	54,723
Other securities pledged	122,392
Total securities pledged as collateral	$	419,303

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 September 30, 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)
September 30, 2017
U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations	$	537,162	$	(4,765	)	$	456,330	$	(12,597	)	$	993,492	$	(17,362	)
State and municipal securities	75,499		(700		)	45,328		(1,561		)	120,827		(2,261		)
U.S. government agency and government-sponsored enterprise securities	173,027		(665		)	21,517		(565		)	194,544		(1,230		)
U.S. government securities	250		(1		)	—		—			250		(1		)
Other securities	2,278		(36		)	2,740		(216		)	5,018		(252		)
Total	$	788,216	$	(6,167	)	$	525,915	$	(14,939	)	$	1,314,131	$	(21,106	)

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 September 30, 2017, there were 168 U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations securities in an unrealized loss position, of which 84 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 September 30, 2017.

At September 30, 2017, there were 107 state and municipal government securities in an unrealized loss position, of which 40 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 September 30, 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 September 30, 2017.

At September 30, 2017, there were 22 U.S. government agency and government-sponsored enterprise securities in an unrealized loss position, of which five 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 September 30, 2017.

At September 30, 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 September 30, 2017.

At September 30, 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 September 30, 2017 as it has the intent and ability to hold these investments for sufficient time to allow for recovery in the market value.