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	$ 35,862us-gaap_NetIncomeLoss	$ 43,646us-gaap_NetIncomeLoss
Other comprehensive income (loss), net of tax:
Net unrealized holding gains on securities available for sale arising during period (tax effects of $11,756 and $13,616)	21,833	25,289
Reclassification adjustment for gains on securities available for sale included in net income (tax effects of $(00) and $(2,838))	(1)	(5,270)
Reclassification adjustment for impairment charges on available for sale securities included in net income (tax effects of $79 and $31)	148	59
Other comprehensive income (loss), net of tax	21,980	20,078
Comprehensive income	$ 57,842us-gaap_ComprehensiveIncomeNetOfTax	$ 63,724us-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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