Note 6 - Investment Securities (Tables)

3 Months Ended

Mar. 31, 2014

Investments, Debt and Equity Securities [Abstract]

Schedule of Amortized Cost Gross Unrealized Gains Gross Unrealized Losses and Fair Values of Investment [Table text Block]

	March 31, 2014
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	475,139	$	120	$	-	$	475,259
Mortgage-backed securities		969,042		1,860		49,749		921,153
Collateralized mortgage obligations		82		-		39		43
Corporate debt securities		165,716		423		3,458		162,681
Mutual funds		6,000		-		243		5,757
Preferred stock of government sponsored entities		535		12,909		-		13,444
Other equity securities		500		60		-		560
Total securities available-for-sale	$	1,617,014	$	15,372	$	53,489	$	1,578,897
Total investment securities	$	1,617,014	$	15,372	$	53,489	$	1,578,897

	December 31, 2013
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	460,095	$	99	$	1	$	460,193
Mortgage-backed securities		1,010,294		7,049		64,529		952,814
Collateralized mortgage obligations		5,929		231		54		6,106
Asset-backed securities		123		-		-		123
Corporate debt securities		154,955		298		4,949		150,304
Mutual funds		6,000		-		275		5,725
Preferred stock of government sponsored entities		569		10,834		-		11,403
Total securities available-for-sale	$	1,637,965	$	18,511	$	69,808	$	1,586,668
Total investment securities	$	1,637,965	$	18,511	$	69,808	$	1,586,668

Schedule of Amortized Cost and Fair Value of Investment Securities by Contractual Maturities [Table Text Block]

	Securities available-for-sale
	Amortized cost		Fair value
	(In thousands)
Due in one year or less	$	385,848	$	385,941
Due after one year through five years		178,382		179,513
Due after five years through ten years		100,805		98,143
Due after ten years (1)		951,979		915,300
Total	$	1,617,014	$	1,578,897

Fair Value, Unrealized Losses, and Number of Issuances of the Temporarily Impaired Securities [Table Text Block]

	March 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
Mortgage-backed securities	$	888,606	$	49,748	$	151	$	1	$	888,757	$	49,749
Collateralized mortgage obligations		-		-		43		39		43		39
Corporate debt securities		25,778		2		96,544		3,456		122,322		3,458
Mutual funds		-		-		5,757		243		5,757		243
Total securities available-for-sale	$	914,384	$	49,750	$	102,495	$	3,739	$	1,016,879	$	53,489
Total investment securities	$	914,384	$	49,750	$	102,495	$	3,739	$	1,016,879	$	53,489

	December 31, 2013
	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	$	75,064	$	1	$	-	$	-	$	75,064	$	1
Mortgage-backed securities		792,012		64,526		272		2		792,284		64,528
Mortgage-backed securities-Non-agency		94		1		-		-		94		1
Collateralized mortgage obligations		68		4		301		50		369		54
Corporate debt securities		9,970		30		100,081		4,919		110,051		4,949
Mutual funds		-		-		5,724		275		5,724		275
Total securities available-for-sale	$	877,208	$	64,562	$	106,378	$	5,246	$	983,586	$	69,808
Total investment securities	$	877,208	$	64,562	$	106,378	$	5,246	$	983,586	$	69,808