Securities (Tables)

9 Months Ended

Sep. 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)
September 30, 2016
U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations	$	1,498,158	$	17,148	$	(2,382	)	$	1,512,924
State and municipal securities	487,308		16,192		(382		)	503,118
U.S. government agency and government-sponsored enterprise securities	333,423		5,009		(140		)	338,292
U.S. government securities	548		—		—			548
Other securities	5,284		64		(146		)	5,202
Total	$	2,324,721	$	38,413	$	(3,050	)	$	2,360,084
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				Nine Months Ended
	September 30,				September 30,
	2016		2015		2016		2015
	(in thousands)
Gross realized gains	$	572	$	236	$	1,174	$	1,310
Gross realized losses	—		—		—		(10		)
Net realized gains	$	572	$	236	$	1,174	$	1,300

Schedule of Contractual Maturities of Investment Securities Available for Sale

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

	September 30, 2016
	Amortized Cost		Fair Value
	(in thousands)
Due within one year	$	28,765	$	28,874
Due after one year through five years	484,206		493,479
Due after five years through ten years	688,715		703,388
Due after ten years	1,117,751		1,129,141
Other securities with no stated maturity	5,284		5,202
Total investment securities available-for-sale	$	2,324,721	$	2,360,084

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, 2016
	(in thousands)
Washington and Oregon State to secure public deposits	$	235,931
Federal Reserve Bank to secure borrowings	40,877
Other securities pledged	147,336
Total securities pledged as collateral	$	424,144

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, 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)
September 30, 2016
U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations	$	176,508	$	(548	)	$	163,859	$	(1,834	)	$	340,367	$	(2,382	)
State and municipal securities	35,915		(337		)	3,489		(45		)	39,404		(382		)
U.S. government agency and government-sponsored enterprise securities	22,115		(140		)	—		—			22,115		(140		)
Other securities	—		—			2,810		(146		)	2,810		(146		)
Total	$	234,538	$	(1,025	)	$	170,158	$	(2,025	)	$	404,696	$	(3,050	)
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	)