Securities (Tables)

9 Months Ended

Sep. 30, 2017

Available-for-sale Securities [Abstract]

Securities Available for Sale

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

Schedule of gross realized gains and losses on sales and calls of securities available for sale

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

Schedule of Contractual Maturities of Investment Securities Available for Sale

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

Carrying Value of Securities Pledged As Collateral

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

Summary of Gross Unrealized Losses and Fair Value of the Investments with Unrealized Losses

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	)