Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Securities available-for-sale, amortized cost	$ 2,087,069	$ 1,680,491
Unearned income on loans	$ (59,374)	$ (68,282)
Common stock, par value	$ 0us-gaap_CommonStockNoParValue	$ 0us-gaap_CommonStockNoParValue
Common stock, shares authorized	63,033us-gaap_CommonStockSharesAuthorized	63,033us-gaap_CommonStockSharesAuthorized
Common stock, outstanding	57,437us-gaap_CommonStockSharesOutstanding	51,265us-gaap_CommonStockSharesOutstanding

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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Face amount per share of no-par value common stock.

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Amount of deferred interest and fee income, unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of acquired loans. Excludes amounts for loans and leases covered under loss sharing agreements.

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