Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Operating Activities
Net income	$ 57,005	$ 55,407
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	1,047	1,361
Net amortization of investment securities premiums and discounts	13,376	14,606
Loans held for sale originated or acquired	(449,630)	(293,098)
Proceeds from sales of loans held for sale	460,799	298,399
Gain on sale of loans	(13,030)	(8,373)
Loss on sale of investments	93	99
Stock-based compensation expense, net of tax benefits	700	437
Excess tax (benefits) deficiencies from stock-based compensation	(102)	14
Depreciation of premises and equipment	6,658	5,545
Loss (gain) on sale of other real estate owned and write-downs, net	619	(969)
Amortization of core deposit intangibles	1,486	1,403
Net (increase) decrease in accrued interest receivable	(3,173)	133
Net decrease (increase) in other assets	3,983	(1,870)
Net decrease in accrued interest payable	(496)	(342)
Net (decrease) increase in other liabilities	(2,405)	2,960
Net cash provided by operating activities	76,930	75,712
Investing Activities
Sales of available-for-sale securities	35,558	16,639
Maturities, prepayments and calls of available-for-sale securities	346,230	309,569
Purchases of available-for-sale securities	(347,212)	(121,671)
Maturities, prepayments and calls of held-to-maturity securities	10,065	3,930
Purchases of held-to-maturity securities	(83,004)	(7,873)
Principal collected on loans	723,316	630,875
Loans originated or acquired	(967,774)	(783,843)
Net addition of premises and equipment and other real estate owned	(7,403)	(5,614)
Proceeds from sale of other real estate owned	6,288	6,730
Net sale (purchase) of non-marketable equity securities	29,877	(523)
Net cash received in acquisitions	19,712	0
Net cash (used in) provided by investing activities	(234,347)	48,219
Financing Activities
Net increase in deposits	66,625	165,869
Net increase in securities sold under agreements to repurchase	10,472	1,846
Net decrease in short-term Federal Home Loan Bank advances	0	(256,000)
Proceeds from long-term Federal Home Loan Bank advances	50,000	175,000
Repayments of long-term Federal Home Loan Bank advances	(19,410)	(151,877)
Net decrease in other borrowed funds	(575)	(949)
Cash dividends paid	(36,188)	(11,942)
Excess tax benefits (deficiencies) from stock-based compensation	102	(14)
Stock-based compensation activity	(299)	837
Net cash provided by (used in) financing activities	70,727	(77,230)
Net (decrease) increase in cash and cash equivalents	(86,690)	46,701
Cash and cash equivalents at beginning of period	442,409	155,657
Cash and cash equivalents at end of period	355,719	202,358
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest	15,248	13,510
Cash paid during the period for income taxes	15,961	16,818
Supplemental Disclosure of Non-Cash Investing Activities
Transfer of investment securities from available-for-sale to held-to-maturity	0	484,583
Sale and refinancing of other real estate owned	265	501
Transfer of loans to other real estate owned	5,181	5,740
Fair value of common stock shares issued	10,776	0
Cash consideration for outstanding shares	12,219	0
Fair value of assets acquired	174,637	0
Liabilities assumed	$ 152,779	$ 0