Securities (Tables)

3 Months Ended

Mar. 31, 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)
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

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

Schedule of Contractual Maturities of Investment Securities Available for Sale

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

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:

	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

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 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	)