Note 4 - Investment Securities (Tables)

12 Months Ended

Dec. 31, 2013

Investments, Debt and Equity Securities [Abstract]

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

	As of December 31, 2013
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized 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	$	1,637,695	$	18,511	$	69,808	$	1,586,668

	As of December 31, 2012
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
	(In thousands)
Securities Held-to-Maturity
State and municipal securities	$	129,037	$	9,268	$	-	$	138,305
Mortgage-backed securities		634,757		40,801		-		675,558
Corporate debt securities		9,974		69		-		10,043
Total securities held-to-maturity	$	773,768	$	50,138	$	-	$	823,906
Securities Available-for-Sale
U.S. treasury securities	$	509,748	$	228	$	5	$	509,971
Mortgage-backed securities		404,505		12,194		5		416,694
Collateralized mortgage obligations		9,772		430		34		10,168
Asset-backed securities		145		-		4		141
Corporate debt securities		349,973		106		14,102		335,977
Mutual funds		6,000		79		-		6,079
Preferred stock of government sponsored entities		569		1,766		-		2,335
Trust preferred securities		9,964		151		-		10,115
Total securities available-for-sale	$	1,290,676	$	14,954	$	14,150	$	1,291,480
Total investment securities	$	2,064,444	$	65,092	$	14,150	$	2,115,386

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	$	460,106	$	460,204
Due after one year through five years		80,769		82,079
Due after five years through ten years		112,654		108,840
Due after ten years (1)		984,436		935,545
Total	$	1,637,965	$	1,586,668

Schedule of Unrealized Loss on Investments [Table Text Block]

	As of December 31, 2013
	Temporarily Impaired Securities
	Less than 12 months						12 months or longer						Total
	Fair Value		Unrealized Losses		No. of Issuances		Fair Value		Unrealized Losses		No. of Issuances		Fair Value		Unrealized Losses		No. of Issuances
	(Dollars in thousands)
Securities Available-for-Sale
U.S. treasury securities	$	75,064	$	1		1	$	-	$	-		-	$	75,064	$	1		1
Mortgage-backed securities		792,012		64,526		25		272		2		7		792,284		64,528		32
Mortgage-backed securities-Non-agency		94		1		1		-		-		-		94		1		1
Collateralized mortgage obligations		68		4		2		301		50		3		369		54		5
Corporate debt securities		9,970		30		1		100,081		4,919		8		110,051		4,949		9
Mutual funds		-		-		-		5,724		275		1		5,724		275		1
Total securities available-for-sale	$	877,208	$	64,562		30	$	106,378	$	5,246		19	$	983,586	$	69,808		49

	As of December 31, 2012
	Temporarily Impaired Securities
	Less than 12 months						12 months or longer						Total
	Fair Value		Unrealized Losses		No. of Issuances		Fair Value		Unrealized Losses		No. of Issuances		Fair Value		Unrealized Losses		No. of Issuances
	(Dollars in thousands)
Securities Held-to-Maturity
Total securities held-to-maturity	$	-	$	-		-	$	-	$	-		-	$	-	$	-		-
Securities Available-for-Sale
U.S. treasury securities	$	49,969	$	5		1	$	-	$	-		-	$	49,969	$	5		1
Mortgage-backed securities		231		1		2		170		1		6		401		2		8
Mortgage-backed securities-Non-agency		-		-		-		96		2		1		96		2		1
Collateralized mortgage obligations		-		-		-		439		35		4		439		35		4
Asset-backed securities		-		-		-		141		4		1		141		4		1
Corporate debt securities		52,468		2,532		4		253,430		11,570		22		305,898		14,102		26
Total securities available-for-sale	$	102,668	$	2,538		7	$	254,276	$	11,612		34	$	356,944	$	14,150		41