Securities

9 Months Ended

Sep. 30, 2016

Marketable Securities [Abstract]

Securities [Text Block]

Securities

Trading Securities

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

	September 30, 2016					December 31, 2015					September 30, 2015
	Fair Value		Net Unrealized Gain (Loss)			Fair Value		Net Unrealized Gain (Loss)			Fair Value		Net Unrealized Gain (Loss)
U.S. government agency debentures	$	15,705	$	(7	)	$	61,295	$	(71	)	$	42,431	$	(38	)
U.S. government agency residential mortgage-backed securities	464,749		876			10,989		17			30,973		195
Municipal and other tax-exempt securities	54,856		(100		)	31,901		210			84,261		421
Other trading securities	11,305		14			18,219		(16		)	23,466		28
Total trading securities	$	546,615	$	783		$	122,404	$	140		$	181,131	$	606

Investment Securities

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

	September 30, 2016
	Amortized		Carrying		Fair		Gross Unrealized1
	Cost		Value		Value		Gain		Loss
Municipal and other tax-exempt	$	323,225	$	323,225	$	327,788	$	4,745	$	(182	)
U.S. government agency residential mortgage-backed securities – Other	22,166		22,166		23,452		1,286		—
Other debt securities	201,066		201,066		229,070		28,014		(10		)
Total investment securities	$	546,457	$	546,457	$	580,310	$	34,045	$	(192	)

¹  Gross unrealized gains and losses are not recognized in Accumulated Other Comprehensive Income "AOCI" in the Consolidated Balance Sheets.

	December 31, 2015
	Amortized		Carrying		Fair		Gross Unrealized1
	Cost		Value		Value		Gain		Loss
Municipal and other tax-exempt	$	365,258	$	365,258	$	368,910	$	3,935	$	(283	)
U.S. government agency residential mortgage-backed securities – Other	26,721		26,833		27,874		1,063		(22		)
Other debt securities	205,745		205,745		232,375		26,689		(59		)
Total investment securities	$	597,724	$	597,836	$	629,159	$	31,687	$	(364	)

¹  Gross unrealized gains and losses are not recognized in AOCI in the Consolidated Balance Sheets.

	September 30, 2015
	Amortized		Carrying		Fair		Gross Unrealized1
	Cost		Value		Value		Gain		Loss
Municipal and other tax-exempt	$	379,980	$	379,980	$	384,310	$	4,461	$	(131	)
U.S. government agency residential mortgage-backed securities – Other	28,456		28,653		30,080		1,427		—
Other debt securities	203,751		203,751		228,701		25,063		(113		)
Total investment securities	$	612,187	$	612,384	$	643,091	$	30,951	$	(244	)

¹  Gross unrealized gains and losses are not recognized in AOCI in the Consolidated Balance Sheets.

The amortized cost and fair values of investment securities at September 30, 2016, 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:
Carrying value	$	87,330		$	195,763		$	8,778		$	31,354		$	323,225		2.76
Fair value	87,331			196,864			9,023			34,570			327,788
Nominal yield¹	1.42		%	2.01		%	3.20		%	6.08		%	2.28		%
Other debt securities:
Carrying value	15,047			42,314			125,955			17,750			201,066			6.84
Fair value	15,191			45,802			148,422			19,655			229,070
Nominal yield	3.49		%	5.03		%	5.88		%	4.86		%	5.43		%
Total fixed maturity securities:
Carrying value	$	102,377		$	238,077		$	134,733		$	49,104		$	524,291		4.32
Fair value	102,522			242,666			157,445			54,225			556,858
Nominal yield	1.72		%	2.54		%	5.70		%	5.64		%	3.48		%
Residential mortgage-backed securities:
Carrying value													$	22,166		³
Fair value													23,452
Nominal yield4													2.75		%
Total investment securities:
Carrying value													$	546,457
Fair value													580,310
Nominal yield													3.46		%

¹  Calculated on a taxable equivalent basis using a 39 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 4.3 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

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

	September 30, 2016
	Amortized		Fair		Gross Unrealized1
	Cost		Value		Gain		Loss			OTTI²
U.S. Treasury	$	1,000	$	1,002	$	2	$	—		$	—
Municipal and other tax-exempt	41,943		42,092		602		(453		)	—
Residential mortgage-backed securities:
U. S. government agencies:
FNMA	3,035,041		3,101,136		67,859		(1,764		)	—
FHLMC	1,611,887		1,641,178		29,640		(349		)	—
GNMA	924,176		926,358		3,530		(1,348		)	—
Other	—		—		—		—			—
Total U.S. government agencies	5,571,104		5,668,672		101,029		(3,461		)	—
Private issue:
Alt-A loans	47,039		54,065		7,230		—			(204		)
Jumbo-A loans	61,377		67,538		6,187		(26		)	—
Total private issue	108,416		121,603		13,417		(26		)	(204		)
Total residential mortgage-backed securities	5,679,520		5,790,275		114,446		(3,487		)	(204		)
Commercial mortgage-backed securities guaranteed by U.S. government agencies	2,942,988		2,986,495		45,329		(1,822		)	—
Other debt securities	4,400		4,151		—		(249		)	—
Perpetual preferred stock	15,562		19,578		4,016		—			—
Equity securities and mutual funds	17,337		18,690		1,370		(17		)	—
Total available for sale securities	$	8,702,750	$	8,862,283	$	165,765	$	(6,028	)	$	(204	)

¹ Gross unrealized gain/loss recognized in AOCI in the consolidated balance sheet.

² Amounts represent unrealized loss that remains in AOCI after an other-than-temporary credit loss has been recognized in income.

	December 31, 2015
	Amortized		Fair		Gross Unrealized¹
	Cost		Value		Gain		Loss			OTTI²
U.S. Treasury	$	1,000	$	995	$	—	$	(5	)	$	—
Municipal and other tax-exempt	56,681		56,817		873		(737		)	—
Residential mortgage-backed securities:
U. S. government agencies:
FNMA	3,156,214		3,187,215		41,502		(10,501		)	—
FHLMC	1,940,915		1,949,335		14,727		(6,307		)	—
GNMA	763,967		761,801		2,385		(4,551		)	—
Other	—		—		—		—			—
Total U.S. government agencies	5,861,096		5,898,351		58,614		(21,359		)	—
Private issue:
Alt-A loans	56,387		62,574		6,574		—			(387		)
Jumbo-A loans	71,724		76,544		5,260		—			(440		)
Total private issue	128,111		139,118		11,834		—			(827		)
Total residential mortgage-backed securities	5,989,207		6,037,469		70,448		(21,359		)	(827		)
Commercial mortgage-backed securities guaranteed by U.S. government agencies	2,919,044		2,905,796		5,396		(18,644		)	—
Other debt securities	4,400		4,151		—		(249		)	—
Perpetual preferred stock	17,171		19,672		2,501		—			—
Equity securities and mutual funds	17,121		17,833		752		(40		)	—
Total available for sale securities	$	9,004,624	$	9,042,733	$	79,970	$	(41,034	)	$	(827	)

¹ Gross unrealized gain/loss recognized in AOCI in the consolidated balance sheet.

² Amounts represent unrealized loss that remains in AOCI after an other-than-temporary credit loss has been recognized in income.

	September 30, 2015
	Amortized		Fair		Gross Unrealized1
	Cost		Value		Gain		Loss			OTTI²
U.S. Treasury	$	1,000	$	1,003	$	3	$	—		$	—
Municipal and other tax-exempt	57,610		57,960		1,065		(715		)	—
Residential mortgage-backed securities:
U. S. government agencies:
FNMA	3,115,810		3,185,097		69,757		(470		)	—
FHLMC	1,853,379		1,885,201		32,646		(824		)	—
GNMA	741,212		744,647		4,557		(1,122		)	—
Other	3,922		4,182		260		—			—
Total U.S. government agencies	5,714,323		5,819,127		107,220		(2,416		)	—
Private issue:
Alt-A loans	58,801		64,700		6,519		—			(620		)
Jumbo-A loans	75,258		80,982		6,121		—			(397		)
Total private issue	134,059		145,682		12,640		—			(1,017		)
Total residential mortgage-backed securities	5,848,382		5,964,809		119,860		(2,416		)	(1,017		)
Commercial mortgage-backed securities guaranteed by U.S. government agencies	2,708,931		2,735,787		28,889		(2,033		)	—
Other debt securities	4,400		4,150		—		(250		)	—
Perpetual preferred stock	17,171		19,163		2,030		(38		)	—
Equity securities and mutual funds	18,711		18,217		950		(1,444		)	—
Total available for sale securities	$	8,656,205	$	8,801,089	$	152,797	$	(6,896	)	$	(1,017	)

¹  Gross unrealized gain/loss recognized in AOCI in the consolidated balance sheet.

²  Amounts represent unrealized loss that remains in AOCI after an other-than-temporary credit loss has been recognized in income.

The amortized cost and fair values of available for sale securities at September 30, 2016, 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 Maturity5
U.S. Treasuries:
Amortized cost	$	—		$	1,000		$	—		$	—			$	1,000		1.29
Fair value	—			1,002			—			—				1,002
Nominal yield	—		%	0.87		%	—		%	—		%		0.87		%
Municipal and other tax-exempt:
Amortized cost	$	9,089		$	13,593		$	2,092		$	17,169			$	41,943		8.14
Fair value	9,190			13,858			2,109			16,935				42,092
Nominal yield¹	4.97		%	3.85		%	3.46		%	2.36		%	6	3.46		%
Commercial mortgage-backed securities:
Amortized cost	$	—		$	931,761		$	1,817,166		$	194,061			$	2,942,988		6.82
Fair value	—			942,994			1,848,462			195,039				2,986,495
Nominal yield	—		%	1.74		%	1.84		%	1.54		%		1.79		%
Other debt securities:
Amortized cost	$	—		$	—		$	—		$	4,400			$	4,400		30.91
Fair value	—			—			—			4,151				4,151
Nominal yield	—		%	—		%	—		%	1.71		%	6	1.71		%
Total fixed maturity securities:
Amortized cost	$	9,089		$	946,354		$	1,819,258		$	215,630			$	2,990,331		6.87
Fair value	9,190			957,854			1,850,571			216,125				3,033,740
Nominal yield	4.97		%	1.77		%	1.85		%	1.61		%		1.81		%
Residential mortgage-backed securities:
Amortized cost														$	5,679,520		2
Fair value														5,790,275
Nominal yield4														1.87		%
Equity securities and mutual funds:
Amortized cost														$	32,899		³
Fair value														38,268
Nominal yield														—		%
Total available-for-sale securities:
Amortized cost														$	8,702,750
Fair value														8,862,283
Nominal yield														1.84		%

¹  Calculated on a taxable equivalent basis using a 39 percent effective tax rate.

²  The average expected lives of mortgage-backed securities were 3.4 years years based upon current prepayment assumptions.

³  Primarily common stock and preferred stock of corporate issuers with no stated maturity.

⁴  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.

⁵  Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without penalty.

⁶  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 days.

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

	Three Months Ended September 30,						Nine Months Ended September 30,
	2016			2015			2016			2015
Proceeds	$	232,239		$	450,765		$	1,027,379		$	1,164,425
Gross realized gains	2,415			3,803			11,705			13,543
Gross realized losses	(21		)	(1,637		)	(21		)	(3,617		)
Related federal and state income tax expense	931			843			4,545			3,861

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):

	Sept. 30,2016		Dec. 31, 2016		Sept. 30,2015
Investment:
Carrying value	$	301,754	$	231,033	$	50,380
Fair value	307,264		234,382		52,249
Available for sale:
Amortized cost	7,098,721		6,831,743		6,225,689
Fair value	7,213,520		6,849,524		6,318,330

The secured parties do not have the right to sell or re-pledge these securities.

Temporarily Impaired Securities as of September 30, 2016

(in thousands):

	Number of Securities	Less Than 12 Months				12 Months or Longer				Total
		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Investment:
Municipal and other tax-exempt	75	$	100,624	$	106	$	4,359	$	76	$	104,983	$	182
U.S. government agency residential mortgage-backed securities – Other	—	—		—		—		—		—		—
Other debt securities	3	444		6		856		4		1,300		10
Total investment securities	78	$	101,068	$	112	$	5,215	$	80	$	106,283	$	192

	Number of Securities	Less Than 12 Months				12 Months or Longer				Total
		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Available for sale:
Municipal and other tax-exempt	20	$	2,210	$	3	$	6,396	$	450	$	8,606	$	453
Residential mortgage-backed securities:
U. S. government agencies:
FNMA	14	365,201		1,712		14,229		52		379,430		1,764
FHLMC	6	122,713		91		20,306		258		143,019		349
GNMA	16	230,043		1,157		212,705		191		442,748		1,348
Total U.S. government agencies	36	717,957		2,960		247,240		501		965,197		3,461
Private issue1:
Alt-A loans	5	8,231		141		7,773		63		16,004		204
Jumbo-A loans	1	6,583		26		—		—		6,583		26
Total private issue	6	14,814		167		7,773		63		22,587		230
Total residential mortgage-backed securities	42	732,771		3,127		255,013		564		987,784		3,691
Commercial mortgage-backed securities guaranteed by U.S. government agencies	33	372,805		1,656		60,851		166		433,656		1,822
Other debt securities	2	—		—		4,151		249		4,151		249
Perpetual preferred stocks	—	—		—		—		—		—		—
Equity securities and mutual funds	33	86		—		886		17		972		17
Total available for sale securities	130	$	1,107,872	$	4,786	$	327,297	$	1,446	$	1,435,169	$	6,232

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, 2015

(In thousands)

	Number of Securities	Less Than 12 Months				12 Months or Longer				Total
		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Investment:
Municipal and other tax-exempt	73	$	127,319	$	207	$	13,380	$	77	$	140,699	$	284
U.S. government agency residential mortgage-backed securities – Other	1	5,533		22		—		—		5,533		22
Other debt securities	11	1,082		41		1,715		18		2,797		59
Total investment securities	85	$	133,934	$	270	$	15,095	$	95	$	149,029	$	365

	Number of Securities	Less Than 12 Months				12 Months or Longer				Total
		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Available for sale:
U.S. Treasury	1	$	995	$	5	$	—	$	—	$	995	$	5
Municipal and other tax-exempt	20	$	9,909	$	27	$	11,664	$	710	$	21,573	$	737
Residential mortgage-backed securities:
U. S. government agencies:
FNMA	55	1,188,022		10,262		18,236		239		1,206,258		10,501
FHLMC	40	726,713		4,827		77,545		1,480		804,258		6,307
GNMA	15	364,919		1,951		102,109		2,600		467,028		4,551
Total U.S. government agencies	110	2,279,654		17,040		197,890		4,319		2,477,544		21,359
Private issue1:
Alt-A loans	4	—		—		9,264		387		9,264		387
Jumbo-A loans	8	—		—		8,482		440		8,482		440
Total private issue	12	—		—		17,746		827		17,746		827
Total residential mortgage-backed securities	122	2,279,654		17,040		215,636		5,146		2,495,290		22,186
Commercial mortgage-backed securities guaranteed by U.S. government agencies	213	1,582,469		11,419		484,258		7,225		2,066,727		18,644
Other debt securities	2	—		—		4,151		249		4,151		249
Perpetual preferred stocks	—	—		—		—		—		—		—
Equity securities and mutual funds	61	782		5		991		35		1,773		40
Total available for sale securities	419	$	3,873,809	$	28,496	$	716,700	$	13,365	$	4,590,509	$	41,861

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 September 30, 2015

(In thousands)

	Number of Securities	Less Than 12 Months				12 Months or Longer				Total
		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Investment:
Municipal and other tax-exempt	15	$	6,250	$	81	$	13,438	$	50	$	19,688	$	131
U.S. government agency residential mortgage-backed securities – Other	—	—		—		—		—		—		—
Other debt securities	17	1,283		64		4,577		49		5,860		113
Total investment securities	32	$	7,533	$	145	$	18,015	$	99	$	25,548	$	244

	Number of Securities	Less Than 12 Months				12 Months or Longer				Total
		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Available for sale:
Municipal and other tax-exempt1	18	$	7,868	$	485	$	3,800	$	230	$	11,668	$	715
Residential mortgage-backed securities:
U. S. government agencies:
FNMA	6	155,747		470		—		—		155,747		470
FHLMC	4	71,930		503		26,848		321		98,778		824
GNMA	4	54,701		562		54,701		560		109,402		1,122
Total U.S. government agencies	14	282,378		1,535		81,549		881		363,927		2,416
Private issue1:
Alt-A loans	4	2,857		186		6,667		434		9,524		620
Jumbo-A loans	8	5,380		236		3,681		161		9,061		397
Total private issue	12	8,237		422		10,348		595		18,585		1,017
Total residential mortgage-backed securities	26	290,615		1,957		91,897		1,476		382,512		3,433
Commercial mortgage-backed securities guaranteed by U.S. government agencies	31	327,790		1,488		223,007		545		550,797		2,033
Other debt securities	2	—		—		4,149		250		4,149		250
Perpetual preferred stocks	1	1,912		38		—		—		1,912		38
Equity securities and mutual funds	37	4,031		1,432		526		12		4,557		1,444
Total available for sale securities	115	$	632,216	$	5,400	$	323,379	$	2,513	$	955,595	$	7,913

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

On a quarterly basis, the Company performs separate evaluations of impaired debt and equity investments and available for sale securities to determine if the unrealized losses are temporary.

For debt securities, management determines whether it intends to sell or if it is more-likely-than-not that it will be required to sell impaired securities. This determination considers current and forecasted liquidity requirements, regulatory and capital requirements and securities portfolio management. Based on this evaluation as of September 30, 2016, the Company does not intend to sell any impaired available for sale securities before fair value recovers to the current amortized cost and it is more-likely-than-not that the Company will not be required to sell impaired securities before fair value recovers, which may be maturity.

Impairment of debt securities rated investment grade by all nationally-recognized rating agencies is considered temporary unless specific contrary information is identified. None of the debt securities rated investment grade were considered to be other-than-temporarily impaired at September 30, 2016.

At September 30, 2016, the composition of the Company’s investment and available for sale securities portfolios by the lowest current credit rating assigned by any of the three nationally-recognized rating agencies is as follows (in thousands):

	AAA - AA				A - BBB				Below Investment Grade				Not Rated				Total
	Carrying Value		Fair Value		Carrying Value		Fair Value		Carrying Value		Fair Value		Carrying Value		Fair Value		Carrying Value		Fair Value
Investment:
Municipal and other tax-exempt	$	207,881	$	209,210	$	5,094	$	5,160	$	—	$	—	$	110,250	$	113,418	$	323,225	$	327,788
U.S. government agency residential mortgage-backed securities 1	—		—		—		—		—		—		22,166		23,452		22,166		23,452
Other debt securities	140,184		164,118		—		—		—		—		60,882		64,952		201,066		229,070
Total investment securities	$	348,065	$	373,328	$	5,094	$	5,160	$	—	$	—	$	193,298	$	201,822	$	546,457	$	580,310

	AAA - AA				A - BBB				Below Investment Grade				Not Rated				Total
	Amortized Cost		Fair Value		Amortized Cost		Fair Value		Amortized Cost		Fair Value		Amortized Cost		Fair Value		Amortized Cost		Fair Value
Available for Sale:
U.S. Treasury	$	—	$	—	$	—	$	—	$	—	$	—	$	1,000	$	1,002	$	1,000	$	1,002
Municipal and other tax-exempt	23,837		24,290		5,675		5,316		—		—		12,431		12,486		41,943		42,092
U.S. government agency residential mortgage-backed securities 1	—		—		—		—		—		—		5,571,104		5,668,672		5,571,104		5,668,672
Privately issued residential mortgage-backed securities	—		—		—		—		108,416		121,603		—		—		108,416		121,603
Commercial mortgage-backed securities guaranteed by U.S. government agencies	—		—		—		—		—		—		2,942,988		2,986,495		2,942,988		2,986,495
Other debt securities	4,400		4,151		—		—		—		—		—		—		4,400		4,151
Perpetual preferred stock	—		—		4,796		5,505		10,766		14,073		—		—		15,562		19,578
Equity securities and mutual funds	4		591		—		—		—		—		17,333		18,099		17,337		18,690
Total available for sale securities	$	28,241	$	29,032	$	10,471	$	10,821	$	119,182	$	135,676	$	8,544,856	$	8,686,754	$	8,702,750	$	8,862,283

¹  U.S. government and government sponsored enterprises are not rated by the nationally-recognized rating agencies as these securities are guaranteed by agencies of the U.S. government or government-sponsored enterprises.

At September 30, 2016, the entire portfolio of privately issued residential mortgage-backed securities was rated below investment grade by the nationally-recognized rating agencies. The gross unrealized loss on these securities totaled $230 thousand. Impairment of securities rated below investment grade was evaluated based on projections of estimated cash flows from individual loans underlying each security using current and anticipated unemployment and default rates, changes in housing prices and estimated liquidation costs at foreclosure. Each factor is considered in the evaluation.

The primary assumptions used in this evaluation were:

	September 30, 2016	Dec. 31, 2015	September 30, 2015
Unemployment rate	Moving down to 4.7 percent over the next 12 months and remain at 4.7 percent thereafter.	Decreasing to 4.8 percent over the next 12 months and remain at 4.8 percent thereafter.	Moving down to 5.1 percent over the next 12 months and remain at 5.1 percent thereafter.
Housing price appreciation/depreciation	Starting with current depreciated housing prices based on information derived from the FHFA1, appreciating 3.5 percent over the next 12 months, then flat for the following 12 months and then appreciating at 2 percent per year thereafter.	Starting with current depreciated housing prices based on information derived from the FHFA1, appreciating 3.5 percent over the next 12 months, then flat for the following 12 months and then appreciating at 2 percent per year thereafter.	Starting with current depreciated housing prices based on information derived from the FHFA1, appreciating 3.2 percent over the next 12 months, then flat for the following 12 months and then appreciating at 2 percent per year thereafter.
Estimated liquidation costs	Reflect actual historical liquidations costs observed on Jumbo and Alt-A residential mortgage loans in securities owned by the Company.	Reflect actual historical liquidations costs observed on Jumbo and Alt-A residential mortgage loans in securities owned by the Company.	Reflect actual historical liquidations costs observed on Jumbo and Alt-A residential mortgage loans in securities owned by the Company.
Discount rates	Estimated cash flows were discounted at rates that range from 2.00 percent to 6.25 percent based on our current expected yields.	Estimated cash flows were discounted at rates that range from 2.00 percent to 6.25 percent based on our current expected yields.	Estimated cash flows were discounted at rates that range from 2.00 percent to 6.25 percent based on our current expected yields.

¹  Federal Housing Finance Agency

Credit loss impairment is recorded as a charge to earnings. Additional impairment based on the difference between the total unrealized loss and the estimated credit loss on these securities is charged against other comprehensive income, net of deferred taxes. No credit loss impairments were recognized in earnings on privately issued residential mortgage-backed securities during the three months ended September 30, 2016.

A distribution of the amortized cost (after recognition of the other-than-temporary impairment), fair value and credit loss impairments recognized on our privately issued residential mortgage-backed securities is as follows (in thousands, except for number of securities):

						Credit Losses Recognized
						Three months ended
						September 30, 2016			Life-to-date
	Number of Securities	Amortized Cost		Fair Value		Number of Securities	Amount		Number of Securities	Amount
Alt-A	14	$	47,039	$	54,065	—	$	—	14	$	36,284
Jumbo-A	30	61,377		67,538		—	—		29	18,220
Total	44	$	108,416	$	121,603	—	$	—	43	$	54,504

Impaired equity securities, including perpetual preferred stocks, are evaluated based on management's ability and intent to hold the securities until fair value recovers over periods not to exceed three years. The assessment of the ability and intent to hold these securities focuses on the liquidity needs, asset/liability management objectives and securities portfolio objectives. Factors considered when assessing recovery include forecasts of general economic conditions and specific performance of the issuer, analyst ratings and credit spreads for preferred stocks which have debt-like characteristics. The Company has evaluated the near-term prospects of the investments in relation to the severity and duration of the impairment and based on that evaluation has the ability and intent to hold these investments until a recovery in fair value. Accordingly, all impairment of equity securities was considered temporary at September 30, 2016.

The following is a tabular roll forward of the amount of credit-related OTTI recognized on available for sale debt securities in earnings (in thousands):

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2016		2015		2016		2015
Balance of credit-related OTTI recognized on available for sale debt securities, beginning of period	$	54,504	$	54,439	$	54,504	$	54,347
Additions for credit-related OTTI not previously recognized	—		—		—		—
Additions for increases in credit-related OTTI previously recognized when there is no intent to sell and no requirement to sell before recovery of amortized cost	—		—		—		92
Reductions for change in intent to hold before recovery	—		—		—		—
Sales	—		—		—		—
Balance of credit-related OTTI recognized on available for sale debt securities, end of period	$	54,504	$	54,439	$	54,504	$	54,439

Additions above exclude other-than-temporary impairment recorded due to change in intent to hold before recovery.

Fair Value Option Securities

Fair value option securities represent securities which the Company has elected to carry at fair value and are separately identified on the Consolidated Balance Sheets. Changes in the fair value are recognized in earnings as they occur. Certain U.S. Treasury securities, residential mortgage-backed securities issued by U.S. government agencies and derivative contracts are held as an economic hedge of the mortgage servicing rights. 

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

	Sept. 30,2016					Dec. 31, 2015					Sept. 30, 2015
	Fair Value		Net Unrealized Gain (Loss)			Fair Value		Net Unrealized Gain (Loss)			Fair Value		Net Unrealized Gain (Loss)
U.S. Treasury	$	222,409	$	(2,397	)	$	—	$	—		$	—	$	—
U.S. government agency residential mortgage-backed securities	$	—	$	—		$	444,217	$	(2,060	)	$	427,760	$	2,067
Total	$	222,409	$	(2,397	)	$	444,217	$	(2,060	)	$	427,760	$	2,067

Restricted Equity Securities

Restricted equity securities primarily include stock we are required to hold as members of the Federal Reserve system and the Federal Home Loan Banks. Restricted equity securities are carried at cost as these securities do not have a readily determined fair value because ownership of these shares are restricted and lacks a market. A summary of restricted equity securities follows (in thousands):

	Sept. 30,2016		Dec. 31, 2015		Sept. 30,2015
Federal Reserve stock	$	36,283	$	36,148	$	35,148
Federal Home Loan Bank stock	296,907		237,365		228,268
Other	201		171		171
Total	$	333,391	$	273,684	$	263,587