Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 20,374	$ 17,451	$ 38,985	$ 26,910
Other comprehensive income (loss), net of tax
Net change in fair value of securities available for sale	1,854	(2,228)	5,935	(667)
Net change in fair value of cash flow hedges	(144)	382	(21)	464
Net change in other comprehensive income for defined benefit postretirement plans	61	123	121	199
Total other comprehensive income (loss)	1,771	(1,723)	6,035	(4)
Total comprehensive income	$ 22,145	$ 15,728	$ 45,020	$ 26,906

Net of tax amount of the appreciation (loss) in the value of unsold available-for-sale securities.

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Amount after tax and reclassification adjustments, of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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Amount after tax and reclassification adjustments, of (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement defined benefit plans.

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