Investment Securities (Details 2) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Investment securities available for sale
Amortized Cost	$ 873,981	$ 797,930	$ 800,901
Gross Unrealized Gains	13,715	12,477	10,107
Gross Unrealized Losses	(1,898)	(3,641)	(5,894)
Fair Value	885,798	806,766	805,114
Government-sponsored entities debt
Investment securities available for sale
Amortized Cost	123,926	149,720	140,438
Gross Unrealized Gains	188	191	127
Gross Unrealized Losses	(320)	(1,714)	(3,106)
Fair Value	123,794	148,197	137,459
State and municipal obligations
Investment securities available for sale
Amortized Cost	130,553	133,635	137,733
Gross Unrealized Gains	3,946	4,141	3,834
Gross Unrealized Losses	(161)	(195)	(309)
Fair Value	134,338	137,581	141,258
Mortgage-backed securities.
Investment securities available for sale
Amortized Cost	616,341	511,414	519,569
Gross Unrealized Gains	9,170	7,572	5,608
Gross Unrealized Losses	(438)	(1,040)	(2,168)
Fair Value	625,073	517,946	523,009
Corporate Stocks
Investment securities available for sale
Amortized Cost	3,161	3,161	3,161
Gross Unrealized Gains	411	573	538
Gross Unrealized Losses	(979)	(692)	(311)
Fair Value	$ 2,593	$ 3,042	$ 3,388

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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