Securities (Tables)

6 Months Ended

Jun. 30, 2018

The fair value and net unrealized gain (loss) included in trading securities are as follows (in thousands):



	June 30, 2018				December 31, 2017					June 30, 2017
	Fair Value		Net Unrealized Gain (Loss)		Fair Value		Net Unrealized Gain (Loss)			Fair Value		Net Unrealized Gain (Loss)
U.S. government agency debentures	$	28,750	$	10	$	21,196	$	8		$	20,954	$	(9	)
U.S. government agency residential mortgage-backed securities	1,605,001		1,923		392,673		(517		)	365,171		(1,032		)
Municipal and other tax-exempt securities	70,606		231		13,559		83			45,444		230
Asset-backed securities	193,271		250		23,885		(26		)	—		—
Other trading securities	11,987		32		11,363		4			9,845		(175		)
Total trading securities	$	1,909,615	$	2,446	$	462,676	$	(448	)	$	441,414	$	(986	)

Investment Securities (Held-to-Maturity) [Table Text Block]

The amortized cost and fair values of investment securities are as follows (in thousands):



	June 30, 2018
	Amortized		Fair		Gross Unrealized
	Cost		Value		Gain		Loss
Municipal and other tax-exempt	$	173,097	$	174,205	$	1,779	$	(671	)
U.S. government agency residential mortgage-backed securities	13,989		13,984		232		(237		)
Other debt securities	204,927		215,195		12,259		(1,991		)
Total investment securities	$	392,013	$	403,384	$	14,270	$	(2,899	)



	December 31, 2017
	Amortized		Fair		Gross Unrealized
	Cost		Value		Gain		Loss
Municipal and other tax-exempt	$	228,186	$	230,349	$	2,967	$	(804	)
U.S. government agency residential mortgage-backed securities	15,891		16,242		446		(95		)
Other debt securities	217,716		233,444		17,095		(1,367		)
Total investment securities	$	461,793	$	480,035	$	20,508	$	(2,266	)



	June 30, 2017
	Amortized		Fair		Gross Unrealized
	Cost		Value		Gain		Loss
Municipal and other tax-exempt	$	267,375	$	270,531	$	3,384	$	(228	)
U.S. government agency residential mortgage-backed securities	18,035		18,642		668		(61		)
Other debt securities	205,016		226,502		22,040		(554		)
Total investment securities	$	490,426	$	515,675	$	26,092	$	(843	)

The amortized cost and fair values of investment securities at June 30, 2018, by contractual maturity, are as shown in the following table (dollars in thousands):



	Less than One Year			One to Five Years			Six to Ten Years			Over Ten Years			Total			Weighted Average Maturity²
Municipal and other tax-exempt:
Amortized cost	$	60,535		$	62,005		$	28,117		$	22,440		$	173,097		4.02
Fair value	60,487			61,736			29,038			22,944			174,205
Nominal yield¹	2.07		%	2.58		%	5.81		%	5.12		%	3.25		%
Other debt securities:
Amortized cost	14,877			52,170			123,762			14,118			204,927			5.99
Fair value	15,023			54,233			132,912			13,027			215,195
Nominal yield	3.99		%	4.69		%	5.67		%	4.34		%	5.21		%
Total fixed maturity securities:
Amortized cost	$	75,412		$	114,175		$	151,879		$	36,558		$	378,024		5.08
Fair value	75,510			115,969			161,950			35,971			389,400
Nominal yield	2.45		%	3.54		%	5.69		%	4.82		%	4.31		%
Residential mortgage-backed securities:
Amortized cost													$	13,989		³
Fair value													13,984
Nominal yield⁴													2.76		%
Total investment securities:
Amortized cost													$	392,013
Fair value													403,384
Nominal yield													4.26		%


¹	Calculated on a taxable equivalent basis using a 25 percent effective tax rate.


²	Expected maturities may differ from contractual maturities, because borrowers may have the right to call or prepay obligations with or without penalty.


³	The average expected lives of residential mortgage-backed securities were 5.0 years based upon current prepayment assumptions.


⁴	The nominal yield on residential mortgage-backed securities is based upon prepayment assumptions at the purchase date. Actual yields earned may differ significantly based upon actual prepayments. See Quarterly Financial Summary - Unaudited for current yields on the investment securities portfolio.

Available For Sale Securities [Table Text Block]

The amortized cost and fair value of available for sale securities are as follows (in thousands):



	June 30, 2018
	Amortized		Fair		Gross Unrealized
	Cost		Value		Gain		Loss			OTTI
U.S. Treasury	$	494	$	490	$	—	$	(4	)	$	—
Municipal and other tax-exempt	10,590		10,697		111		(4		)	—
Residential mortgage-backed securities:
U. S. government agencies:
FNMA	3,088,585		3,007,885		2,774		(83,474		)	—
FHLMC	1,580,185		1,538,582		738		(42,341		)	—
GNMA	772,785		758,093		915		(15,607		)	—
Total U.S. government agencies	5,441,555		5,304,560		4,427		(141,422		)	—
Private issue	65,376		83,224		18,221		—			(373		)
Total residential mortgage-backed securities	5,506,931		5,387,784		22,648		(141,422		)	(373		)
Commercial mortgage-backed securities guaranteed by U.S. government agencies	2,799,953		2,738,451		1,815		(63,317		)	—
Other debt securities	25,500		25,444		12		(68		)	—
Total available for sale securities	$	8,343,468	$	8,162,866	$	24,586	$	(204,815	)	$	(373	)



	December 31, 2017
	Amortized		Fair		Gross Unrealized
	Cost		Value		Gain		Loss			OTTI
U.S. Treasury	$	1,000	$	1,000	$	—	$	—		$	—
Municipal and other tax-exempt	27,182		27,080		181		(283		)	—
Residential mortgage-backed securities:
U. S. government agencies:
FNMA	3,021,551		2,997,563		11,549		(35,537		)	—
FHLMC	1,545,971		1,531,009		3,148		(18,110		)	—
GNMA	787,626		780,580		1,607		(8,653		)	—
Total U.S. government agencies	5,355,148		5,309,152		16,304		(62,300		)	—
Private issue	74,311		93,221		19,301		—			(391		)
Total residential mortgage-backed securities	5,429,459		5,402,373		35,605		(62,300		)	(391		)
Commercial mortgage-backed securities guaranteed by U.S. government agencies	2,858,885		2,834,961		1,963		(25,887		)	—
Other debt securities	25,500		25,481		50		(69		)	—
Perpetual preferred stock	12,562		15,767		3,205		—			—
Equity securities and mutual funds	14,487		14,916		515		(86		)	—
Total available for sale securities	$	8,369,075	$	8,321,578	$	41,519	$	(88,625	)	$	(391	)



	June 30, 2017
	Amortized		Fair		Gross Unrealized
	Cost		Value		Gain		Loss			OTTI
U.S. Treasury	$	1,000	$	998	$	—	$	(2	)	$	—
Municipal and other tax-exempt	32,885		32,765		293		(413		)	—
Residential mortgage-backed securities:
U. S. government agencies:
FNMA	3,005,920		3,008,531		24,213		(21,602		)	—
FHLMC	1,412,376		1,412,472		7,785		(7,689		)	—
GNMA	938,086		936,365		3,641		(5,362		)	—
Other	25,000		25,009		52		(43		)	—
Total U.S. government agencies	5,381,382		5,382,377		35,691		(34,696		)	—
Private issue	86,656		103,383		16,727		—			—
Total residential mortgage-backed securities	5,468,038		5,485,760		52,418		(34,696		)	—
Commercial mortgage-backed securities guaranteed by U.S. government agencies	2,788,543		2,782,070		7,804		(14,277		)	—
Other debt securities	4,400		4,152		—		(248		)	—
Perpetual preferred stock	12,562		16,568		4,006		—			—
Equity securities and mutual funds	17,572		18,728		1,219		(63		)	—
Total available for sale securities	$	8,325,000	$	8,341,041	$	65,740	$	(49,699	)	$	—

The amortized cost and fair values of available for sale securities at June 30, 2018, by contractual maturity, are as shown in the following table (dollars in thousands):



	Less than One Year			One to Five Years			Six to Ten Years			Over Ten Years				Total			Weighted Average Maturity⁴
U.S. Treasuries:
Amortized cost	$	—		$	494		$	—		$	—			$	494		1.59
Fair value	—			490			—			—				490
Nominal yield	—		%	1.99		%	—		%	—		%		1.99		%
Municipal and other tax-exempt:
Amortized cost	$	4,574		$	2,303		$	—		$	3,713			$	10,590		6.53
Fair value	4,580			2,401			—			3,716				10,697
Nominal yield¹	3.45		%	6.27		%	—		%	3.98		%	⁵	4.25		%
Commercial mortgage-backed securities:
Amortized cost	$	8,070		$	987,244		$	1,548,520		$	256,119			$	2,799,953		6.89
Fair value	8,041			968,540			1,512,106			249,764				2,738,451
Nominal yield	1.67		%	1.96		%	2.17		%	2.20		%		2.10		%
Other debt securities:
Amortized cost	$	—		$	—		$	—		$	25,500			$	25,500		14.18
Fair value	—			—			—			25,444				25,444
Nominal yield	—		%	—		%	—		%	1.59		%	⁵	1.59		%
Total fixed maturity securities:
Amortized cost	$	12,644		$	990,041		$	1,548,520		$	285,332			$	2,836,537		6.95
Fair value	12,621			971,431			1,512,106			278,924				2,775,082
Nominal yield	2.31		%	1.97		%	2.17		%	2.17		%		2.10		%
Residential mortgage-backed securities:
Amortized cost														$	5,506,931		²
Fair value														5,387,784
Nominal yield³														2.16		%
Total available-for-sale securities:
Amortized cost														$	8,343,468
Fair value														8,162,866
Nominal yield														2.14		%


¹	Calculated on a taxable equivalent basis using a 25 percent effective tax rate.


²	The average expected lives of mortgage-backed securities were 4.3 years years based upon current prepayment assumptions.


³	The nominal yield on mortgage-backed securities is based upon prepayment assumptions at the purchase date. Actual yields earned may differ significantly based upon actual prepayments. See Quarterly Financial Summary –– Unaudited following for current yields on available for sale securities portfolio.


⁴	Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without penalty.


⁵	Nominal yield on municipal and other tax-exempt securities and other debt securities with contractual maturity dates over ten years are based on variable rates which generally are reset within 35.

Sales of available for sale securities resulted in gains and losses as follows (in thousands):



	Three Months Ended June 30,						Six Months Ended June 30,
	2018			2017			2018			2017
Proceeds	$	142,743		$	460,402		$	187,533		$	700,412
Gross realized gains	257			2,763			450			4,855
Gross realized losses	(1,019		)	(2,383		)	(1,502		)	(2,426		)
Related federal and state income tax expense (benefit)	(194		)	148			(268		)	945

Securities Pledged As Collateral [Table Text Block]

A summary of investment and available for sale securities that have been pledged as collateral for repurchase agreements, public trust funds on deposit and for other purposes, as required by law was as follows (in thousands):



	June 30, 2018		Dec. 31, 2017		June 30, 2017
Investment:
Amortized cost	$	172,906	$	226,852	$	251,684
Fair value	174,240		229,429		255,097

Available for sale:
Amortized cost	6,821,287		7,151,468		6,327,666
Fair value	6,653,875		7,089,346		6,317,623

Schedule of Unrealized Loss on Investments [Table Text Block]

Temporarily Impaired Securities as of June 30, 2018

(in thousands):



	Number of Securities	Less Than 12 Months				12 Months or Longer				Total
	Number of Securities	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Investment:
Municipal and other tax-exempt	84	$	98,325	$	484	$	5,007	$	187	$	103,332	$	671
U.S. government agency residential mortgage-backed securities	3	6,979		110		2,809		127		9,788		237
Other debt securities	80	36,131		1,795		3,324		196		39,455		1,991
Total investment securities	167	$	141,435	$	2,389	$	11,140	$	510	$	152,575	$	2,899



	Number of Securities	Less Than 12 Months				12 Months or Longer				Total
	Number of Securities	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Available for sale:
U.S. Treasury	1	$	490	$	4	$	—	$	—	$	490	$	4
Municipal and other tax-exempt	10	4,784		3		495		1		5,279		4
Residential mortgage-backed securities:
U. S. government agencies:
FNMA	174	2,049,432		44,860		710,962		38,614		2,760,394		83,474
FHLMC	93	1,116,337		26,663		339,515		15,678		1,455,852		42,341
GNMA	33	275,104		5,611		220,740		9,996		495,844		15,607
Total U.S. government agencies	300	3,440,873		77,134		1,271,217		64,288		4,712,090		141,422
Private issue¹	8	5,409		373		—		—		5,409		373
Total residential mortgage-backed securities	308	3,446,282		77,507		1,271,217		64,288		4,717,499		141,795
Commercial mortgage-backed securities guaranteed by U.S. government agencies	211	1,675,839		42,732		554,819		20,585		2,230,658		63,317
Other debt securities	2	—		—		20,434		68		20,434		68
Total available for sale securities	532	$	5,127,395	$	120,246	$	1,846,965	$	84,942	$	6,974,360	$	205,188


¹	Includes securities for which an unrealized loss remains in AOCI after an other-than-temporary credit loss has been recognized in income.

Temporarily Impaired Securities as of December 31, 2017

(In thousands)



	Number of Securities	Less Than 12 Months				12 Months or Longer				Total
	Number of Securities	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Investment:
Municipal and other tax-exempt	100	$	145,960	$	643	$	5,833	$	161	$	151,793	$	804
U.S. government agency residential mortgage-backed securities	1	—		—		3,356		95		3,356		95
Other debt securities	49	20,091		1,238		3,076		129		23,167		1,367
Total investment securities	150	$	166,051	$	1,881	$	12,265	$	385	$	178,316	$	2,266



	Number of Securities	Less Than 12 Months				12 Months or Longer				Total
	Number of Securities	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Available for sale:
U.S. Treasury	—	$	—	$	—	$	—	$	—	$	—	$	—
Municipal and other tax-exempt	19	12,765		18		4,802		265		17,567		283
Residential mortgage-backed securities:
U. S. government agencies:
FNMA	113	1,203,041		9,618		824,029		25,919		2,027,070		35,537
FHLMC	69	863,778		7,297		385,816		10,813		1,249,594		18,110
GNMA	27	201,887		1,452		248,742		7,201		450,629		8,653
Total U.S. government agencies	209	2,268,706		18,367		1,458,587		43,933		3,727,293		62,300
Private issue¹	8	5,898		391		—		—		5,898		391
Total residential mortgage-backed securities	217	2,274,604		18,758		1,458,587		43,933		3,733,191		62,691
Commercial mortgage-backed securities guaranteed by U.S. government agencies	185	1,465,703		11,824		652,296		14,063		2,117,999		25,887
Other debt securities	2	19,959		41		472		28		20,431		69
Perpetual preferred stocks	—	—		—		—		—		—		—
Equity securities and mutual funds	111	911		7		2,203		79		3,114		86
Total available for sale securities	534	$	3,773,942	$	30,648	$	2,118,360	$	58,368	$	5,892,302	$	89,016


¹	Includes securities for which an unrealized loss remains in AOCI after an other-than-temporary credit loss has been recognized in income.

Temporarily Impaired Securities as of June 30, 2017

(In thousands)



	Number of Securities	Less Than 12 Months				12 Months or Longer				Total
	Number of Securities	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Investment:
Municipal and other tax-exempt	82	$	111,078	$	149	$	3,000	$	79	$	114,078	$	228
U.S. government agency residential mortgage-backed securities	1	3,810		61		—		—		3,810		61
Other debt securities	22	8,384		554		—		—		8,384		554
Total investment securities	105	$	123,272	$	764	$	3,000	$	79	$	126,272	$	843



	Number of Securities	Less Than 12 Months				12 Months or Longer				Total
	Number of Securities	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Available for sale:
U.S. Treasury	1	$	997	$	2	$	—	$	—	$	997	$	2
Municipal and other tax-exempt	13	1,957		1		4,655		412		6,612		413
Residential mortgage-backed securities:
U. S. government agencies:
FNMA	75	1,381,687		20,288		87,371		1,314		1,469,058		21,602
FHLMC	42	731,853		7,213		16,388		476		748,241		7,689
GNMA	21	291,806		3,766		76,605		1,596		368,411		5,362
Other	1	19,957		43		—		—		19,957		43
Total U.S. government agencies	139	2,425,303		31,310		180,364		3,386		2,605,667		34,696
Private issue¹	—	—		—		—		—		—		—
Total residential mortgage-backed securities	139	2,425,303		31,310		180,364		3,386		2,605,667		34,696
Commercial mortgage-backed securities guaranteed by U.S. government agencies	121	1,388,406		12,690		78,828		1,587		1,467,234		14,277
Other debt securities	2	—		—		4,152		248		4,152		248
Perpetual preferred stocks	—	—		—		—		—		—		—
Equity securities and mutual funds	91	1,668		22		887		41		2,555		63
Total available for sale securities	367	$	3,818,331	$	44,025	$	268,886	$	5,674	$	4,087,217	$	49,699


¹	Includes securities for which an unrealized loss remains in AOCI after an other-than-temporary credit loss has been recognized in income.

Fair Value Option Securities [Table Text Block]

The fair value and net unrealized gain (loss) included in fair value option securities is as follows (in thousands):



	June 30, 2018					December 31, 2017					June 30, 2017
	Fair Value		Net Unrealized Gain (Loss)			Fair Value		Net Unrealized Gain (Loss)			Fair Value		Net Unrealized Gain (Loss)
U.S. government agency residential mortgage-backed securities	$	482,227	$	(5,509	)	$	755,054	$	(1,877	)	$	445,169	$	1,247

Schedule of Restricted Equity Securities [Table Text Block]



	June 30, 2018		Dec. 31, 2017		June 30, 2017
Federal Reserve stock	$	41,178	$	40,746	$	36,676
Federal Home Loan Bank stock	306,543		279,200		274,113
Other	—		243		244
Total	$	347,721	$	320,189	$	311,033

- Definition

Tabular disclosure of available-for-sale securities which includes, but is not limited to, changes in the cost basis and fair value, fair value and gross unrealized gain (loss), fair values by type of security, contractual maturity and classification, amortized cost basis, contracts to acquire securities to be accounted for as available-for-sale, debt maturities, transfers to trading, change in net unrealized holding gain (loss) net of tax, continuous unrealized loss position fair value, aggregate losses qualitative disclosures, other than temporary impairment (OTTI) losses or other disclosures related to available for sale securities.

+ References + Details

- Definition

Tabular disclosure of all investments in certain debt and equity securities for which the entity has the positive intent and ability to hold until maturity.

+ References + Details