Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Operating activities
Net cash provided by operating activities	$ 20,260	$ 41,340
Investing activities
Purchases of securities available for sale	(76,282)	(70,720)
Proceeds from sales of securities available for sale	0	9,013
Proceeds from call/maturities of securities available for sale	17,069	21,425
Purchases of securities held to maturity	(128,684)	(59,987)
Proceeds from sales of securities held to maturity	0	4,461
Proceeds from call/maturities of securities held to maturity	57,890	28,590
Net decrease/(increase) in loans	12,038	(3,608)
Purchases of premises and equipment	(2,293)	(2,337)
Net cash used in investing activities	(120,262)	(73,163)
Financing activities
Net increase (decrease) in noninterest-bearing deposits	58,944	(1,149)
Net increase in interest-bearing deposits	103,928	95,103
Net (decrease) increase in short-term borrowings	(2,283)	1,594
Repayment of long-term debt	(989)	(2,197)
Cash paid for dividends	(5,372)	(4,300)
Cash received on exercise of stock-based compensation	0	225
Excess tax benefit from stock-based compensation	741	155
Net cash provided by financing activities	154,969	89,431
Net increase in cash and cash equivalents	54,967	57,608
Cash and cash equivalents at beginning of period	246,648	132,420
Cash and cash equivalents at end of period	301,615	190,028
Supplemental disclosures
Cash paid for interest	6,543	5,779
Cash paid for income taxes	4,993	2,645
Noncash transactions:
Transfers of loans to other real estate owned	$ 2,585	$ 5,828