Securities (Tables)

6 Months Ended

Jun. 30, 2016

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)
June 30, 2016
U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations	$	1,403,591	$	20,196	$	(2,101	)	$	1,421,686
State and municipal securities	500,618		17,913		(166		)	518,365
U.S. government agency and government-sponsored enterprise securities	327,223		6,520		—			333,743
U.S. government securities	548		1		—			549
Other securities	5,284		64		(139		)	5,209
Total	$	2,237,264	$	44,694	$	(2,406	)	$	2,279,552
December 31, 2015
U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations	$	1,296,955	$	4,525	$	(14,991	)	$	1,286,489
State and municipal securities	480,417		12,690		(938		)	492,169
U.S. government agency and government-sponsored enterprise securities	354,515		1,113		(1,846		)	353,782
U.S. government securities	20,439		—		(302		)	20,137
Other securities	5,284		24		(191		)	5,117
Total	$	2,157,610	$	18,352	$	(18,268	)	$	2,157,694

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

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

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2016		2015		2016		2015
	(in thousands)
Gross realized gains	$	229	$	343	$	602	$	1,073
Gross realized losses	—		—		—		(9		)
Net realized gains	$	229	$	343	$	602	$	1,064

Schedule of Contractual Maturities of Investment Securities Available for Sale

The scheduled contractual maturities of investment securities available for sale at June 30, 2016 are presented as follows:

	June 30, 2016
	Amortized Cost		Fair Value
	(in thousands)
Due within one year	$	26,674	$	26,827
Due after one year through five years	462,009		471,463
Due after five years through ten years	698,729		716,521
Due after ten years	1,044,568		1,059,532
Other securities with no stated maturity	5,284		5,209
Total investment securities available-for-sale	$	2,237,264	$	2,279,552

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:

	June 30, 2016
	(in thousands)
Washington and Oregon State to secure public deposits	$	396,321
Federal Reserve Bank to secure borrowings	44,079
Other securities pledged	154,109
Total securities pledged as collateral	$	594,509

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 June 30, 2016 and December 31, 2015:

	Less than 12 Months					12 Months or More					Total
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
	(in thousands)
June 30, 2016
U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations	$	51,222	$	(264	)	$	170,543	$	(1,837	)	$	221,765	$	(2,101	)
State and municipal securities	17,512		(126		)	6,077		(40		)	23,589		(166		)
Other securities	—		—			2,816		(139		)	2,816		(139		)
Total	$	68,734	$	(390	)	$	179,436	$	(2,016	)	$	248,170	$	(2,406	)
December 31, 2015
U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations	$	664,509	$	(7,610	)	$	214,325	$	(7,381	)	$	878,834	$	(14,991	)
State and municipal securities	48,261		(358		)	31,383		(580		)	79,644		(938		)
U.S. government agency and government-sponsored enterprise securities	193,400		(1,128		)	40,034		(718		)	233,434		(1,846		)
U.S. government securities	10,343		(136		)	9,794		(166		)	20,137		(302		)
Other securities	2,300		(15		)	2,780		(176		)	5,080		(191		)
Total	$	918,813	$	(9,247	)	$	298,316	$	(9,021	)	$	1,217,129	$	(18,268	)