CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net Income	$ 16,170	$ 14,611
Net unrealized holding gains/ (losses) on marketable securities:
Unrealized holding gains net of tax of $(1,885) and $(3,579), respectively	2,952	5,596
Reclassification adjustment for gains included in net income, net of tax of $43 and $1,218, respectively	(68)	(1,904)
Net unrealized holding gains on marketable securities	2,884	3,692
Change in fair value of interest rate swaps, net of tax of $(24) and $(135), respectively	44	251
Defined benefit plan:
Reclassification adjustment for prior period service costs included in net income, net of tax of $(140) and $75, respectively	219	(138)
Other comprehensive income	3,147	3,805
Total comprehensive income	$ 19,317us-gaap_ComprehensiveIncomeNetOfTax	$ 18,416us-gaap_ComprehensiveIncomeNetOfTax

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period).

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Amount after tax and reclassification adjustments, of appreciation (loss) in value of unsold available-for-sale securities, attributable to parent entity. Excludes amounts related to other than temporary impairment (OTTI) loss.

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Amount after tax of reclassification adjustment from accumulated other comprehensive (income) loss for prior service cost (credit) related to pension and other postretirement benefit plans.

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Amount after tax of other comprehensive income (loss) attributable to parent entity.

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Amount after tax of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities.

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Amount after tax, before reclassification adjustments, of unrealized holding gain (loss) on available-for-sale securities.

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