Note 6 - Investment Securities

3 Months Ended

Mar. 31, 2016

Investments, Debt and Equity Securities [Abstract]

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

6. Investment Securities

Investment securities were $1.49 billion as of March 31, 2016, compared to $1.59 billion as of December 31, 2015. The following tables reflect the amortized cost, gross unrealized gains, gross unrealized losses, and fair value of investment securities as of March 31, 2016, and December 31, 2015:

	March 31, 2016
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	224,750	$	61	$	7	$	224,804
U.S. government sponsored entities		100,000		10		-		100,010
Mortgage-backed securities		1,063,944		6,553		4		1,070,493
Collateralized mortgage obligations		60		-		26		34
Corporate debt securities		74,957		413		2,267		73,103
Mutual funds		6,000		-		85		5,915
Preferred stock of government sponsored entities		2,811		478		486		2,803
Other equity securities		3,902		4,060		-		7,962
Total	$	1,476,424	$	11,575	$	2,875	$	1,485,124

	December 31, 2015
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	284,678	$	5	$	395	$	284,288
U.S. government sponsored entities		150,000		-		1,840		148,160
Mortgage-backed securities		1,073,108		560		11,399		1,062,269
Collateralized mortgage obligations		63		-		27		36
Corporate debt securities		74,955		425		1,525		73,855
Mutual funds		6,000		-		167		5,833
Preferred stock of government sponsored entities		2,811		633		228		3,216
Other equity securities		4,108		4,929		342		8,695
Total	$	1,595,723	$	6,552	$	15,923	$	1,586,352

The amortized cost and fair value of investment securities as of March 31, 2016, 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	$	154,963	$	154,978
Due after one year through five years		104,879		105,470
Due after five years through ten years		145,501		143,358
Due after ten years (1)		1,071,081		1,081,318
Total	$	1,476,424	$	1,485,124

(1) Equity securities are reported in this category

There were no sales transactions of mortgage-backed securities during the first quarter of 2016. Proceeds of $406.9 million were received from the sale of mortgage-backed securities during the three months ended March 31, 2015. Proceeds from repayments, maturities and calls of mortgage-backed securities were $33.5 million and $12.1 million for the three months ended March 31, 2016 and 2015, respectively. There were no sales transactions of other investment securities during the three months ended March 31, 2016. Proceeds of $335.1 million were received from the sale of other investment securities during the three months ended March 31, 2015. Proceeds from maturities and calls of other investment securities were $110.0 million during the three months ended March 31, 2016 compared to zero during the same period a year ago. No gains and losses were realized on sales of investment securities but a permanent impairment write-down of $206,000 was recorded during the three months ended March 31, 2016 compared to gains of $1.7 million and losses of $1.7 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 March 31, 2016, and December 31, 2015:

	March 31, 2016
	Temporarily impaired securities
	Less than 12 months				12 months or longer				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
	(Dollars in thousands)
Securities Available-for-Sale
U.S. treasury securities	$	29,965	$	7	$	-	$	-	$	29,965	$	7
Mortgage-backed securities		389		3		46		1		435		4
Collateralized mortgage obligations		-		-		34		26		34		26
Corporate debt securities		9,950		50		42,783		2,217		52,733		2,267
Mutual funds		-		-		5,915		85		5,915		85
Preferred stock of government sponsored entities		2,230		486		-		-		2,230		486
Total	$	42,534	$	546	$	48,778	$	2,329	$	91,312	$	2,875

	December 31, 2015
	Temporarily impaired securities
	Less than 12 months				12 months or longer				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
	(Dollars in thousands)
Securities Available-for-Sale
U.S. treasury securities	$	224,289	$	395	$	-	$	-	$	224,289	$	395
U.S. government sponsored entities		148,160		1,840		-		-		148,160		1,840
Mortgage-backed securities		1,025,342		11,398		6		1		1,025,348		11,399
Collateralized mortgage obligations		-		-		36		27		36		27
Corporate debt securities		9,950		50		43,525		1,475		53,475		1,525
Mutual funds		-		-		5,833		167		5,833		167
Preferred stock of government sponsored entities		2,488		228		-		-		2,488		228
Other equity securities		158		342		-		-		158		342
Total	$	1,410,387	$	14,253	$	49,400	$	1,670	$	1,459,787	$	15,923

As of March 31, 2016, the Company had unrealized losses of $2.9 million. The unrealized losses on these securities were primarily attributed to yield curve movement, together with the widened liquidity spread and credit spread. The issuers have not, to the Company’s knowledge, established any cause for default on these securities. Management believes the impairment was temporary and, accordingly, no impairment loss on these 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 $445.6 million as of March 31, 2016, and $449.6 million as of December 31, 2015, were pledged to secure public deposits, other borrowings, treasury tax and loan, and securities sold under agreements to repurchase.