Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 33,510	$ 22,855
Unrealized holding (losses) gains:
Before tax	(25,153)	3,298
Tax effect	6,972	(1,321)
Net of tax	(18,181)	1,977
Derivative Instruments
Before tax	522	(2,220)
Tax effect	(147)	889
Net of tax	375	(1,331)
Total other comprehensive (loss) income	(17,806)	646
Total comprehensive income	$ 15,704	$ 23,501

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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Amount before tax and reclassification adjustments of unrealized holding gain (loss) on available-for-sale securities and unrealized holding gain (loss) related to transfers of securities into the available-for-sale classification and out of the held-to-maturity classification.

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