INVESTMENTS IN DEBT AND EQUITY SECURITIES (Securities Available for Sale) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Maturities With In One Year, Amortized Cost	$ 28,514	$ 14,799
Available-for-sale Securities, Maturities After One Through Five Years, Amortized Cost	169,684	226,796
Available-for-sale Securities, Maturities After Five Through Ten Years, Amortized Cost	139,283	250,522
Available-for-sale Securities, Maturities After Ten Years, Amortized Cost	1,096,365	1,117,065
Carrying value: Total Amortized Cost	1,433,846	1,609,182
Available-for-sale Securities, Gross Unrealized Gains	19,168	22,319
Available-for-sale Securities, Gross Unrealized Losses	(7,325)	(19,756)
Available-for-sale Securities, Fair Value	1,445,689us-gaap_AvailableForSaleSecurities	1,611,745us-gaap_AvailableForSaleSecurities
Available-for-sale Securities Weighted Average Yield	2.25%	2.18%
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value	28,901	14,927
Available-for-sale Securities, Debt Maturities, Year One Through Five, Fair Value	172,561	233,338
Available-for-sale Securities, Debt Maturities, Year Five Through Ten, Fair Value	140,717	250,860
Available-for-sale Securities, Debt Maturities, After Ten Years, Fair Value	1,103,510	1,112,620
Available-for-sale Securities Weighted Average Yield With In One Year	2.64%	2.17%
Available-for-sale Securities Weighted Average Yield After One Through Five Years	1.97%	2.23%
Available-for-sale Securities Weighted Average Yield After Five Through Ten Years	2.58%	1.81%
Available-for-sale Securities Weighted Average Yield After Ten Years	2.23%	2.24%
U.S. Government sponsored agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Maturities With In One Year, Amortized Cost	0	8,450
Available-for-sale Securities, Maturities After One Through Five Years, Amortized Cost	29,942	40,243
Available-for-sale Securities, Maturities After Five Through Ten Years, Amortized Cost	20,119	88,666
Available-for-sale Securities, Maturities After Ten Years, Amortized Cost	180,098	135,679
Carrying value: Total Amortized Cost	230,159	273,038
Available-for-sale Securities, Gross Unrealized Gains	2,129	3,525
Available-for-sale Securities, Gross Unrealized Losses	(557)	(664)
Available-for-sale Securities, Fair Value	231,731	275,899
Available-for-sale Securities Weighted Average Yield	1.39%	1.34%
Residential mortgage-backed [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Maturities With In One Year, Amortized Cost	269	0
Available-for-sale Securities, Maturities After One Through Five Years, Amortized Cost	65,433	43,943
Available-for-sale Securities, Maturities After Five Through Ten Years, Amortized Cost	48,174	115,731
Available-for-sale Securities, Maturities After Ten Years, Amortized Cost	885,896	951,454
Carrying value: Total Amortized Cost	999,772	1,111,128
Available-for-sale Securities, Gross Unrealized Gains	14,189	12,873
Available-for-sale Securities, Gross Unrealized Losses	(6,117)	(18,214)
Available-for-sale Securities, Fair Value	1,007,844	1,105,787
Available-for-sale Securities Weighted Average Yield	2.39%	2.32%
Commercial mortgage-backed [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Maturities With In One Year, Amortized Cost	0	0
Available-for-sale Securities, Maturities After One Through Five Years, Amortized Cost	779	0
Available-for-sale Securities, Maturities After Five Through Ten Years, Amortized Cost	0	793
Available-for-sale Securities, Maturities After Ten Years, Amortized Cost	0	0
Carrying value: Total Amortized Cost	779	793
Available-for-sale Securities, Gross Unrealized Gains	58	63
Available-for-sale Securities, Gross Unrealized Losses	0	0
Available-for-sale Securities, Fair Value	837	856
Available-for-sale Securities Weighted Average Yield	4.95%	4.94%
State and political subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Maturities With In One Year, Amortized Cost	863	1,369
Available-for-sale Securities, Maturities After One Through Five Years, Amortized Cost	571	2,035
Available-for-sale Securities, Maturities After Five Through Ten Years, Amortized Cost	0	200
Available-for-sale Securities, Maturities After Ten Years, Amortized Cost	28,371	28,432
Carrying value: Total Amortized Cost	29,805	32,036
Available-for-sale Securities, Gross Unrealized Gains	33	81
Available-for-sale Securities, Gross Unrealized Losses	(223)	(560)
Available-for-sale Securities, Fair Value	29,615	31,557
Available-for-sale Securities Weighted Average Yield	1.05%	1.26%
Corporate notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Maturities With In One Year, Amortized Cost	27,382	4,980
Available-for-sale Securities, Maturities After One Through Five Years, Amortized Cost	72,959	140,575
Available-for-sale Securities, Maturities After Five Through Ten Years, Amortized Cost	70,990	45,132
Available-for-sale Securities, Maturities After Ten Years, Amortized Cost	0	0
Carrying value: Total Amortized Cost	171,331	190,687
Available-for-sale Securities, Gross Unrealized Gains	2,759	5,777
Available-for-sale Securities, Gross Unrealized Losses	(395)	(261)
Available-for-sale Securities, Fair Value	173,695	196,203
Available-for-sale Securities Weighted Average Yield	2.75%	2.69%
Equity investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Maturities With In One Year, Amortized Cost	0	0
Available-for-sale Securities, Maturities After One Through Five Years, Amortized Cost	0	0
Available-for-sale Securities, Maturities After Five Through Ten Years, Amortized Cost	0	0
Available-for-sale Securities, Maturities After Ten Years, Amortized Cost	2,000	1,500
Carrying value: Total Amortized Cost	2,000	1,500
Available-for-sale Securities, Gross Unrealized Gains	0	0
Available-for-sale Securities, Gross Unrealized Losses	(33)	(57)
Available-for-sale Securities, Fair Value	1,967	1,443
Available-for-sale Securities Weighted Average Yield	2.15%	2.17%
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value	0	0
Available-for-sale Securities, Debt Maturities, Year One Through Five, Fair Value	0	0
Available-for-sale Securities, Debt Maturities, Year Five Through Ten, Fair Value	0	0
Available-for-sale Securities, Debt Maturities, After Ten Years, Fair Value	1,967	1,443
Debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value	28,901	14,927
Available-for-sale Securities, Debt Maturities, Year One Through Five, Fair Value	172,561	233,338
Available-for-sale Securities, Debt Maturities, Year Five Through Ten, Fair Value	140,717	250,860
Available-for-sale Securities, Debt Maturities, After Ten Years, Fair Value	$ 1,101,543	$ 1,111,177

The percentage of available for sale securities weighted average yield.

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The percentage of available for sale securities weighted average yield, maturing in the fifth through tenth fiscal year following the latest fiscal year.

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The percentage of available for sale securities weighted average yield, maturing in the next fiscal year through the fifth fiscal year following the latest fiscal year.

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The percentage of available for sale securities weighted average yield, maturing after the tenth fiscal year following the latest fiscal year.

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The percentage of available for sale securities weighted average yield, maturing in the next fiscal year following the latest fiscal year.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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Amount after adjustments of available-for-sale debt securities at cost, maturing in the sixth fiscal year through the tenth fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings less cumulative-effect adjustments, and fair value hedge accounting adjustments. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Fair value of available-for-sale debt securities maturing in the sixth fiscal year through the tenth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount after adjustments of available-for-sale debt securities at cost, maturing in the second fiscal year through the fifth fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings less cumulative-effect adjustments, and fair value hedge accounting adjustments. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Fair value of available-for-sale debt securities maturing in the second fiscal year through the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount after adjustments of available-for-sale debt securities at cost, maturing after the tenth fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings less cumulative-effect adjustments, and fair value hedge accounting adjustments. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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