Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating Activities
Net income	$ 117,804	$ 110,410	$ 87,047
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization and accretion	70,759	31,827	22,427
Provision for loan losses	31,090	31,302	33,641
Deferred tax expenses	15,291	29,251	7,063
Net securities gains	(808)	(305)	(3,652)
Other-than-temporary impairment losses on securities	27	212	66
Tax (benefit) expense of stock-based compensation	(1,326)	(386)	61
Loans originated for sale	(219,324)	(255,064)	(166,104)
Loans sold	243,782	245,474	167,298
Gain on sale of loans	(3,845)	(3,887)	(2,768)
Net change in:
Interest receivable	(1,675)	(1,569)	1,416
Interest payable	(2,173)	(3,925)	(1,602)
Trading securities	125,800	331,972	110,490
Bank owned life insurance	(3,598)	(6,130)	(842)
Other, net	14,280	34,848	34,989
Net cash flows provided by operating activities	386,084	544,030	289,530
Investing Activities
Net increase in loans	(683,559)	(409,590)	(412,462)
Securities available for sale:
Purchases	(375,222)	(924,747)	(429,831)
Sales	22,047	87,101	101,973
Maturities	345,528	450,064	431,219
Securities held to maturity:
Purchases	(373,136)	(526,252)	(243,461)
Sales	17,428	2,903
Maturities	285,765	340,401	262,307
Purchase of bank owned life insurance	(10,016)	(25,032)	(34)
Withdrawal/surrender of bank owned life insurance		20,891
Increase in premises and equipment	(14,882)	(12,780)	(17,115)
Net cash received in business combinations	141,637	203,538	23,374
Net cash flows used in investing activities	(644,410)	(793,503)	(284,030)
Financing Activities
Non-interest bearing deposits, savings, and NOW accounts	458,153	614,100	298,833
Time deposits	(312,242)	(337,822)	(196,520)
Short-term borrowings	143,703	218,904	72,580
Increase in long-term debt	92,583	40,315	52,827
Decrease in long-term debt	(113,967)	(197,568)	(166,144)
Decrease in junior subordinated debt	(134,021)
Net proceeds from issuance of preferred stock	106,882
Net proceeds from issuance of common stock	62,092	8,895	71,053
Tax benefit (expense) of stock-based compensation	1,326	386	(61)
Cash dividends paid	(71,246)	(67,646)	(60,686)
Net cash flows (used in) provided by financing activities	233,263	279,564	71,882
Net Increase (Decrease) in Cash and Cash Equivalents	(25,063)	30,091	77,382
Cash and cash equivalents at beginning of year	239,044	208,953	131,571
Cash and Cash Equivalents at End of Year	$ 213,981	$ 239,044	$ 208,953