INVESTMENTS IN DEBT AND EQUITY SECURITIES (Tables)

12 Months Ended

Dec. 31, 2014

Investments, Debt and Equity Securities [Abstract]

Available-for-sale Securities [Table Text Block]

The amortized cost, contractual maturity, gross unrealized gains and losses and fair value of investment securities available for sale at December 31, 2014 and 2013 were as follows:

	Maturity									Total Amortized Cost	Gross Unrealized				Weighted Average Yield
(dollars in thousands)	1 Year or Less			1-5 Years		5-10 Years		After 10 Years			Gains	Losses		Fair Value
December 31, 2014:
Carrying value:
U.S. Government sponsored agencies	$	—		29,942		20,119		180,098		230,159	2,129	(557	)	231,731	1.39	%
Residential mortgage-backed	269			65,433		48,174		885,896		999,772	14,189	(6,117	)	1,007,844	2.39
Commercial mortgage-backed	—			779		—		—		779	58	—		837	4.95
State and political subdivisions	863			571		—		28,371		29,805	33	(223	)	29,615	1.05
Corporate notes	27,382			72,959		70,990		—		171,331	2,759	(395	)	173,695	2.75
Equity investments	—			—		—		2,000		2,000	—	(33	)	1,967	2.15
Total	$	28,514		169,684		139,283		1,096,365		1,433,846	19,168	(7,325	)	1,445,689	2.25
Fair value:
Debt securities	$	28,901		172,561		140,717		1,101,543
Equity securities	—			—		—		1,967
Total	$	28,901		172,561		140,717		1,103,510
Weighted average yield	2.64		%	1.97	%	2.58	%	2.23	%
December 31, 2013:
Carrying value:
U.S. Government sponsored agencies	$	8,450		40,243		88,666		135,679		273,038	3,525	(664	)	275,899	1.34	%
Residential mortgage-backed	—			43,943		115,731		951,454		1,111,128	12,873	(18,214	)	1,105,787	2.32
Commercial mortgage-backed	—			—		793		—		793	63	—		856	4.94
State and political subdivisions	1,369			2,035		200		28,432		32,036	81	(560	)	31,557	1.26
Corporate notes	4,980			140,575		45,132		—		190,687	5,777	(261	)	196,203	2.69
Equity investments	—			—		—		1,500		1,500	—	(57	)	1,443	2.17
Total	$	14,799		226,796		250,522		1,117,065		1,609,182	22,319	(19,756	)	1,611,745	2.18
Fair value:
Debt securities	$	14,927		233,338		250,860		1,111,177
Equity securities	—			—		—		1,443
Total	$	14,927		233,338		250,860		1,112,620
Weighted average yield	2.17		%	2.23	%	1.81	%	2.24	%

Held-to-maturity Securities [Table Text Block]

The amortized cost, contractual maturity, gross unrealized gains and losses and fair value of investment securities held to maturity at December 31, 2014 and 2013 were as follows:

	Maturity									Total Amortized Cost	Gross Unrealized				Weighted Average Yield
(dollars in thousands)	1 Year or Less			1-5 Years		5-10 Years		After 10 Years			Gains	Losses		Fair Value
December 31, 2014:
Carrying value:
U.S. Government sponsored agencies	$	—		—		10,725		—		10,725	42	—		10,767	1.25	%
Residential mortgage-backed	—			105,660		50,512		448,905		605,077	1,931	(5,782	)	601,226	1.86
State and political subdivisions	561			335		489		961		2,346	1	(68	)	2,279	1.68
Total	$	561		105,995		61,726		449,866		618,148	1,974	(5,850	)	614,272	1.85
Fair value:
Debt securities	$	561		106,147		62,000		445,564
Weighted average yield	3.07		%	1.88	%	1.13	%	1.94	%
December 31, 2013:
Carrying value:
U.S. Government sponsored agencies	$	—		—		16,119		—		16,119	—	(153	)	15,966	1.14	%
Residential mortgage-backed	—			16,327		182,933		522,504		721,764	441	(21,206	)	700,999	1.88
State and political subdivisions	640			575		55		1,033		2,303	2	(87	)	2,218	1.93
Total	$	640		16,902		199,107		523,537		740,186	443	(21,446	)	719,183	1.86
Fair value:
Debt securities	$	642		16,926		195,647		505,968
Weighted average yield	3.32		%	2.20	%	1.53	%	1.97	%

Schedule of Realized Gain (Loss) [Table Text Block]

Gross realized gains and gross realized losses on investment securities for the years ended December 31, 2014, 2013 and 2012 were as follows:

(dollars in thousands)	2014			2013		2012
Gross realized gains on sales of available-for-sale securities	$	5,063		802		1,675
Gross realized losses on sales of available-for-sale securities	(3,374		)	(354	)	(374	)
Other-than-temporary impairment	(3		)	(412	)	(2	)
Gross realized gains on calls of investment securities	—			—		7
Net realized gain on investment securities	$	1,686		36		1,306

Schedule of Unrealized Loss on Investments [Table Text Block]

Gross unrealized losses on investment securities and the fair value of the related securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, at December 31, 2014 and 2013, were as follows:

	Less than 12 months				12 months or more			Total
(dollars in thousands)	Fair Value		Unrealized Losses		Fair Value	Unrealized Losses		Fair Value	Unrealized Losses
December 31, 2014:
Available for sale:
U.S. Government sponsored agencies	$	79,207	(427	)	14,600	(130	)	93,807	(557	)
Residential mortgage-backed	204,378		(1,154	)	191,644	(4,963	)	396,022	(6,117	)
State and political subdivisions	28,148		(223	)	—	—		28,148	(223	)
Corporate notes	9,650		(350	)	4,955	(45	)	14,605	(395	)
Equity investments	1,967		(33	)	—	—		1,967	(33	)
Total	$	323,350	(2,187	)	211,199	(5,138	)	534,549	(7,325	)
Held to maturity:
Residential mortgage-backed	$	28,371	(112	)	325,820	(5,670	)	354,191	(5,782	)
State and political subdivisions	641		(3	)	896	(65	)	1,537	(68	)
Total:	$	29,012	(115	)	326,716	(5,735	)	355,728	(5,850	)
December 31, 2013:
Available for sale:
U.S. Government sponsored agencies	$	16,005	(664	)	—	—		16,005	(664	)
Residential mortgage-backed	511,617		(18,119	)	5,473	(95	)	517,090	(18,214	)
State and political subdivisions	27,872		(560	)	—	—		27,872	(560	)
Corporate notes	9,959		(41	)	4,780	(220	)	14,739	(261	)
Equity investments	1,443		(57	)	—	—		1,443	(57	)
Total	$	566,896	(19,441	)	10,253	(315	)	577,149	(19,756	)
Held to maturity:
U.S. Government sponsored agencies	$	15,966	(153	)	—	—		15,966	(153	)
Residential mortgage-backed	644,700		(20,759	)	10,527	(447	)	655,227	(21,206	)
State and political subdivisions	946		(87	)	—	—		946	(87	)
Total:	$	661,612	(20,999	)	10,527	(447	)	672,139	(21,446	)