Securities (Tables)

12 Months Ended

Dec. 31, 2015

Investments, Debt and Equity Securities [Abstract]

Schedule of Amortized Cost and Fair Value of Securities Available for Sale

The amortized cost and fair value of securities are as follows:

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Securities Available for Sale:
December 31, 2015
U.S. Treasury	$	29,738	$	58	$	—		$	29,796
U.S. government-sponsored entities		368,463		856		(1,325	)		367,994
Residential mortgage-backed securities:
Agency mortgage-backed securities		703,069		4,594		(2,832	)		704,831
Agency collateralized mortgage obligations		503,328		1,032		(8,530	)		495,830
Non-agency collateralized mortgage obligations		1,177		13		—			1,190
Commercial mortgage-backed securities		4,299		—		(12	)		4,287
States of the U.S. and political subdivisions		10,748		309		—			11,057
Other debt securities		14,729		208		(651	)		14,286
Total debt securities		1,635,551		7,070		(13,350	)		1,629,271
Equity securities		975		324		(3	)		1,296
	$	1,636,526	$	7,394	$	(13,353	)	$	1,630,567
December 31, 2014
U.S. Treasury	$	29,604	$	78	$	—		$	29,682
U.S. government-sponsored entities		338,330		742		(1,939	)		337,133
Residential mortgage-backed securities:
Agency mortgage-backed securities		546,572		7,548		(35	)		554,085
Agency collateralized mortgage obligations		580,601		1,617		(9,047	)		573,171
Non-agency collateralized mortgage obligations		1,414		17		—			1,431
Commercial mortgage-backed securities		7,891		—		(11	)		7,880
States of the U.S. and political subdivisions		12,713		477		(32	)		13,158
Other debt securities		16,615		420		(857	)		16,178
Total debt securities		1,533,740		10,899		(11,921	)		1,532,718
Equity securities		1,031		316		—			1,347
	$	1,534,771	$	11,215	$	(11,921	)	$	1,534,065
December 31, 2013
U.S. government-sponsored entities	$	336,763	$	126	$	(5,904	)	$	330,985
Residential mortgage-backed securities:
Agency mortgage-backed securities		247,880		4,304		(1,303	)		250,881
Agency collateralized mortgage obligations		511,098		895		(20,794	)		491,199
Non-agency collateralized mortgage obligations		1,747		15		—			1,762
States of the U.S. and political subdivisions		16,842		410		(250	)		17,002
Collateralized debt obligations		37,203		4,507		(10,115	)		31,595
Other debt securities		16,505		524		(929	)		16,100
Total debt securities		1,168,038		10,781		(39,295	)		1,139,524
Equity securities		1,444		682		—			2,126
	$	1,169,482	$	11,463	$	(39,295	)	$	1,141,650

Schedule of Amortized Cost and Fair Value of Securities Held to Maturity

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Securities Held to Maturity:
December 31, 2015
U.S. Treasury	$	500	$	153	$	—		$	653
U.S. government-sponsored entities		137,385		809		(395	)		137,799
Residential mortgage-backed securities:
Agency mortgage-backed securities		709,970		9,858		(1,176	)		718,652
Agency collateralized mortgage obligations		499,694		803		(7,657	)		492,840
Non-agency collateralized mortgage obligations		2,681		14		—			2,695
Commercial mortgage-backed securities		51,258		115		(259	)		51,114
States of the U.S. and political subdivisions		235,573		4,191		(101	)		239,663
	$	1,637,061	$	15,943	$	(9,588	)	$	1,643,416
December 31, 2014
U.S. Treasury	$	502	$	168	$	—		$	670
U.S. government-sponsored entities		101,602		885		(524	)		101,963
Residential mortgage-backed securities:
Agency mortgage-backed securities		677,169		16,712		(346	)		693,535
Agency collateralized mortgage obligations		501,965		1,858		(7,329	)		496,494
Non-agency collateralized mortgage obligations		4,285		28		—			4,313
Commercial mortgage-backed securities		17,560		179		—			17,739
States of the U.S. and political subdivisions		150,272		3,315		(43	)		153,544
	$	1,453,355	$	23,145	$	(8,242	)	$	1,468,258
December 31, 2013
U.S. Treasury	$	503	$	99	$	—		$	602
U.S. government-sponsored entities		43,322		180		(1,151	)		42,351
Residential mortgage-backed securities:
Agency mortgage-backed securities		628,681		12,281		(6,032	)		634,930
Agency collateralized mortgage obligations		385,408		764		(15,844	)		370,328
Non-agency collateralized mortgage obligations		6,852		44		(4	)		6,892
Commercial mortgage-backed securities		2,241		124		(37	)		2,328
States of the U.S. and political subdivisions		132,162		1,992		(2,022	)		132,132
	$	1,199,169	$	15,484	$	(25,090	)	$	1,189,563

Gross Gains and Gross Losses Realized on Sales of Securities

Gross gains and gross losses were realized on securities as follows:

Year Ended December 31	2015			2014			2013
Gross gains	$	831		$	20,241		$	1,200
Gross losses		(9	)		(8,524	)		(392	)
	$	822		$	11,717		$	808

Amortized Cost and Fair Value of Securities, by Contractual Maturities

As of December 31, 2015, the amortized cost and fair value of securities, by contractual maturities, were as follows:

	Available for Sale				Held to Maturity
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Due in one year or less	$	5,178	$	5,183	$	2,409	$	2,426
Due from one to five years		403,591		403,401		136,744		136,841
Due from five to ten years		10,013		10,304		64,954		66,347
Due after ten years		4,896		4,245		169,351		172,501
		423,678		423,133		373,458		378,115
Residential mortgage-backed securities:
Agency mortgage-backed securities		703,069		704,831		709,970		718,652
Agency collateralized mortgage obligations		503,328		495,830		499,694		492,840
Non-agency collateralized mortgage obligations		1,177		1,190		2,681		2,695
Commercial mortgage-backed securities		4,299		4,287		51,258		51,114
Equity securities		975		1,296		—		—
	$	1,636,526	$	1,630,567	$	1,637,061	$	1,643,416

Summaries of Fair Values and Unrealized Losses of Securities, Segregated by Length of Impairment

Following are summaries of the fair values and unrealized losses of securities, segregated by length of impairment:

	Less than 12 Months							Greater than 12 Months							Total
	#		Fair Value		Unrealized Losses			#		Fair Value		Unrealized Losses			#		Fair Value		Unrealized Losses
Securities Available for Sale:
December 31, 2015
U.S. government-sponsored entities		6	$	99,131	$	(814	)		2	$	34,487	$	(511	)		8	$	133,618	$	(1,325	)
Residential mortgage-backed securities:
Agency mortgage-backed securities		19		359,250		(2,832	)		—		—		—			19		359,250		(2,832	)
Agency collateralized mortgage obligations		9		126,309		(1,366	)		18		215,330		(7,164	)		27		341,639		(8,530	)
Commercial mortgage-backed securities		1		4,287		(12	)		—		—		—			1		4,287		(12	)
Other debt securities		—		—		—			3		4,245		(651	)		3		4,245		(651	)
Equity securities		1		632		(3	)		—		—		—			1		632		(3	)
		36	$	589,609	$	(5,027	)		23	$	254,062	$	(8,326	)		59	$	843,671	$	(13,353	)
December 31, 2014
U.S. government-sponsored entities		7	$	89,986	$	(275	)		7	$	99,326	$	(1,664	)		14	$	189,312	$	(1,939	)
Residential mortgage-backed securities:
Agency mortgage-backed securities		2		45,145		(35	)		—		—		—			2		45,145		(35	)
Agency collateralized mortgage obligations		9		166,908		(1,238	)		16		225,700		(7,809	)		25		392,608		(9,047	)
Commercial mortgage-backed securities		1		7,880		(11	)		—		—		—			1		7,880		(11	)
States of the U.S. and political subdivisions		—		—		—			1		1,159		(32	)		1		1,159		(32	)
Other debt securities		—		—		—			4		6,030		(857	)		4		6,030		(857	)
		19	$	309,919	$	(1,559	)		28	$	332,215	$	(10,362	)		47	$	642,134	$	(11,921	)
Securities Held to Maturity:
December 31, 2015
U.S. government-sponsored entities		3	$	39,843	$	(173	)		1	$	14,778	$	(222	)		4	$	54,621	$	(395	)
Residential mortgage-backed securities:
Agency mortgage-backed securities		17		212,024		(1,159	)		1		917		(17	)		18		212,941		(1,176	)
Agency collateralized mortgage obligations		11		150,593		(1,434	)		14		160,716		(6,223	)		25		311,309		(7,657	)
Commercial mortgage-backed securities		3		46,278		(259	)		—		—		—			3		46,278		(259	)
States of the U.S. and political subdivisions		9		17,616		(101	)		—		—		—			9		17,616		(101	)
		43	$	466,354	$	(3,126	)		16	$	176,411	$	(6,462	)		59	$	642,765	$	(9,588	)
December 31, 2014
U.S. government-sponsored entities		2	$	24,989	$	(40	)		2	$	29,516	$	(484	)		4	$	54,505	$	(524	)
Residential mortgage-backed securities:
Agency mortgage-backed securities		1		1,099		(1	)		4		45,042		(345	)		5		46,141		(346	)
Agency collateralized mortgage obligations		8		104,071		(630	)		14		189,642		(6,699	)		22		293,713		(7,329	)
States of the U.S. and political subdivisions		1		1,427		(4	)		4		5,453		(39	)		5		6,880		(43	)
		12	$	131,586	$	(675	)		24	$	269,653	$	(7,567	)		36	$	401,239	$	(8,242	)

Summary of Cumulative Credit-Related OTTI Charges

The following table presents a summary of the cumulative credit-related OTTI charges recognized as components of earnings for securities for which a portion of an OTTI is recognized in other comprehensive income:

	Collateralized Debt Obligations			Equities		Total
For the Year Ended December 31, 2015
Beginning balance	$	—		$	27	$	27
Loss where impairment was not previously recognized		—			—		—
Additional loss where impairment was previously recognized		—			—		—
Reduction due to credit impaired securities sold		—			—		—
Ending balance	$	—		$	27	$	27
For the Year Ended December 31, 2014
Beginning balance	$	17,155		$	27	$	17,182
Loss where impairment was not previously recognized		—			—		—
Additional loss where impairment was previously recognized		—			—		—
Reduction due to credit impaired securities sold		(17,155	)		—		(17,155	)
Ending balance	$	—		$	27	$	27