Note 7 - Investment Securities

9 Months Ended

Sep. 30, 2015

Investments, Debt and Equity Securities [Abstract]

Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]

7. Investment Securities

Investment securities were $1.38 billion at September 30, 2015, compared to $1.32 billion at December 31, 2014. The following tables reflect the amortized cost, gross unrealized gains, gross unrealized losses, and fair value of investment securities as of September 30, 2015, and December 31, 2014:

	September 30, 2015
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	284,603	$	388	$	-	$	284,991
Mortgage-backed securities		1,005,527		1,066		2,195		1,004,398
Collateralized mortgage obligations		67		-		29		38
Corporate debt securities		74,952		370		1,492		73,830
Mutual funds		6,000		-		101		5,899
Preferred stock of government sponsored entities		2,811		1,706		-		4,517
Other equity securities		4,128		3,403		325		7,206
Total	$	1,378,088	$	6,933	$	4,142	$	1,380,879

	December 31, 2014
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	664,206	$	63	$	265	$	664,004
Mortgage-backed securities		549,296		1,393		6,386		544,303
Collateralized mortgage obligations		79		-		34		45
Corporate debt securities		94,943		776		1,247		94,472
Mutual funds		6,000		-		134		5,866
Preferred stock of government sponsored entities		6,276		681		3,733		3,224
Other equity securities		3,608		3,413		-		7,021
Total	$	1,324,408	$	6,326	$	11,799	$	1,318,935

The amortized cost and fair value of investment securities at September 30, 2015, by contractual maturities, are shown below. Actual maturities may differ from contractual maturities because borrowers may have the right to call or repay obligations with or without call or repayment penalties.  

	Securities Available-For-Sale
	Amortized cost		Fair value
	(In thousands)
Due in one year or less	$	184,935	$	185,127
Due after one year through five years		136,610		137,407
Due after five years through ten years		45,546		44,172
Due after ten years (1)		1,010,997		1,014,173
Total	$	1,378,088	$	1,380,879

(1) Equity securities are reported in this category

Proceeds from sales of mortgage-backed securities were $648.0 million during the first nine months of 2015 compared to $458.4 million during the same period a year ago. Proceeds from repayments, maturities and calls of mortgage-backed securities were $67.3 million during the first nine months of 2015 compared to $54.7 million during the same period a year ago. Proceeds from sales of other investment securities were $385.2 million during the first nine months of 2015 compared to $84.9 million during the same period a year ago. Proceeds from maturities and calls of other investment securities were $165.0 million during the first nine months of 2015 compared to $585.8 million during the same period a year ago. Gains of $2.4 million and losses of $1.9 million were realized on sales of investment securities during the first nine months of 2015 compared to gains of $17.1 million and losses of $9.5 million realized during the same period a year ago.

The tables below show the fair value and unrealized losses of the temporarily impaired securities in our investment securities portfolio as of September 30, 2015, and December 31, 2014:

	September 30, 2015
	Temporarily impaired securities
	Less than 12 months				12 months or longer				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Losses		Value		Losses		Value		Losses
	(Dollars in thousands)
Securities Available-for-Sale
Mortgage-backed securities	$	703,710	$	2,194	$	7	$	1	$	703,717	$	2,195
Collateralized mortgage obligations		-		-		38		29		38		29
Corporate debt securities		9,950		50		43,558		1,442		53,508		1,492
Mutual funds		-		-		5,899		101		5,899		101
Other equity securities		175		325		-		-		175		325
Total	$	713,835	$	2,569	$	49,502	$	1,573	$	763,337	$	4,142

	December 31, 2014
	Temporarily impaired securities
	Less than 12 months				12 months or longer				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Losses		Value		Losses		Value		Losses
	(Dollars in thousands)
Securities Available-for-Sale
U.S. treasury securities	$	374,153	$	265	$	-	$	-	$	374,153	$	265
Mortgage-backed securities		-		-		425,090		6,386		425,090		6,386
Collateralized mortgage obligations		-		-		45		34		45		34
Corporate debt securities		-		-		63,753		1,247		63,753		1,247
Mutual funds		-		-		5,866		134		5,866		134
Preferred stock of government sponsored entities		2,448		3,733		-		-		2,448		3,733
Total	$	376,601	$	3,998	$	494,754	$	7,801	$	871,355	$	11,799

Total unrealized losses of $4.1 million at September 30, 2015, were primarily caused by increases in interest rates subsequent to the date that these securities were purchased or caused by the widening of credit and liquidity spreads since the dates of acquisition. The contractual terms of those investments do not permit the issuers to settle the security at a price less than the amortized cost of the investment.

At September 30, 2015, management believed the impairment was temporary and, accordingly, no impairment loss on debt securities has been recognized in our condensed consolidated statements of operations. The Company expects to recover the amortized cost basis of its debt securities, and has no intent to sell and will not be required to sell available-for-sale debt securities that have declined below their cost before their anticipated recovery.

Investment securities having a carrying value of $457.0 million at September 30, 2015, and $591.3 million at December 31, 2014, were pledged to secure public deposits, other borrowings, treasury tax and loan, and securities sold under agreements to repurchase.