Unaudited Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Operating Activities
Net income	$ 55,407	$ 43,470
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	1,361	3,178
Net amortization of investment securities premiums and discounts	14,606	39,846
Loans held for sale originated or acquired	(293,098)	(527,853)
Proceeds from sales of loans held for sale	298,399	616,180
Gain on sale of loans	(8,373)	(16,561)
Loss (gain) on sale of investments	99	(104)
Stock-based compensation expense, net of tax benefits	437	607
Excess tax deficiencies from stock-based compensation	14	188
Depreciation of premises and equipment	5,545	4,742
(Gain) loss on sale of other real estate owned and writedowns, net	(969)	987
Amortization of core deposit intangibles	1,403	991
Net decrease (increase) in accrued interest receivable	133	(3,673)
Net (increase) decrease in other assets	(1,870)	1,584
Net decrease in accrued interest payable	(342)	(1,007)
Net increase in other liabilities	2,960	3,406
Net cash provided by operating activities	75,712	165,981
Investing Activities
Sales of available-for-sale securities	16,639	79,488
Maturities, prepayments and calls of available-for-sale securities	309,569	1,086,493
Purchases of available-for-sale securities	(121,671)	(1,224,241)
Maturities, prepayments and calls of held-to-maturity securities	3,930	0
Purchases of held-to-maturity securities	(7,873)	0
Principal collected on loans	630,875	513,255
Loans originated or acquired	(783,843)	(650,378)
Net addition of premises and equipment and other real estate owned	(5,614)	(3,167)
Proceeds from sale of other real estate owned	6,730	11,066
Net (purchase) sale of non-marketable equity securities	(523)	60
Net cash received from acquisitions	0	12,123
Net cash provided by (used in) investment activities	48,219	(175,301)
Financing Activities
Net increase (decrease) in deposits	165,869	(261,461)
Net increase in securities sold under agreements to repurchase	1,846	10,516
Net (decrease) increase in Federal Home Loan Bank advances	(232,877)	214,965
Net decrease in other borrowed funds	(949)	(1,471)
Cash dividends paid	(11,942)	(10,099)
Excess tax deficiencies from stock-based compensation	(14)	(188)
Proceeds from stock options exercised	837	2,474
Net cash used in financing activities	(77,230)	(45,264)
Net increase (decrease) in cash and cash equivalents	46,701	(54,584)
Cash and cash equivalents at beginning of period	155,657	187,040
Cash and cash equivalents at end of period	202,358	132,456
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest	13,510	15,648
Cash paid during the period for income taxes	16,818	13,660
Supplemental Disclosure of Non-Cash Investing Activities
Transfer of investment securities from available-for-sale to held-to-maturity	484,583	0
Sale and refinancing of other real estate owned	501	2,507
Transfer of loans to other real estate owned	5,740	9,889
Fair value of common stock shares issued	0	28,290
Cash consideration for outstanding shares	0	11,025
Fair value of assets acquired	0	300,541
Liabilities assumed	$ 0	$ 261,226