Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Operating Activities
Net income	$ 90,090	$ 86,619
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	1,194	1,873
Net amortization of investment securities premiums and discounts	19,990	20,082
Loans held for sale originated or acquired	(789,605)	(681,826)
Proceeds from sales of loans held for sale	816,236	719,989
Gain on sale of loans	(23,841)	(20,356)
Loss on sale of investments	706	124
Stock-based compensation expense, net of tax benefits	1,441	737
Excess tax benefits from stock-based compensation	(8)	(102)
Depreciation of premises and equipment	11,440	10,178
(Gain) loss on sale of other real estate owned and write-downs, net	(103)	997
Amortization of core deposit intangibles	2,362	2,206
Net increase in accrued interest receivable	(5,466)	(5,397)
Net increase in other assets	(6,397)	(7,198)
Net decrease in accrued interest payable	(90)	(645)
Net (decrease) increase in other liabilities	(201)	6,547
Net cash provided by operating activities	117,748	133,828
Investing Activities
Sales of available-for-sale securities	20,539	52,691
Maturities, prepayments and calls of available-for-sale securities	527,596	504,062
Purchases of available-for-sale securities	(217,261)	(686,146)
Maturities, prepayments and calls of held-to-maturity securities	21,965	16,762
Purchases of held-to-maturity securities	(1,222)	(148,583)
Principal collected on loans	1,270,573	1,202,256
Loans originated or acquired	(1,755,185)	(1,524,814)
Net decrease (increase) of premises and equipment and other real estate owned	6,610	(10,099)
Proceeds from sale of other real estate owned	8,793	7,769
Net proceeds from sale of non-marketable equity securities	7,608	29,886
Net cash received in acquisitions	6,701	19,712
Net cash used in investing activities	(103,283)	(536,504)
Financing Activities
Net increase in deposits	305,947	181,147
Net (decrease) increase in securities sold under agreements to repurchase	(22,171)	42,578
Net decrease in short-term Federal Home Loan Bank advances	(140,000)	0
Proceeds from Federal Home Loan Bank Borrowings	0	50,000
Repayments of long-term Federal Home Loan Bank advances	(45,558)	(19,581)
Net decrease in other borrowed funds	(538)	(585)
Cash dividends paid	(53,393)	(50,576)
Excess tax benefits from stock-based compensation	8	102
Stock-based compensation activity	(600)	17
Net cash provided by financing activities	43,695	203,102
Net increase (decrease) in cash and cash equivalents	58,160	(199,574)
Cash and cash equivalents at beginning of period	193,253	442,409
Cash and cash equivalents at end of period	251,413	242,835
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest	22,506	22,705
Cash paid during the period for income taxes	25,254	33,912
Supplemental Disclosure of Non-Cash Investing Activities
Sale and refinancing of other real estate owned	611	382
Transfer of loans to other real estate owned	4,117	6,910
Dividend declared but not paid	15,409	14,390
Fair value of common stock shares issued	10,465	10,776
Cash consideration for outstanding shares	3,475	12,219
Fair value of assets acquired	69,750	174,637
Liabilities assumed	$ 62,225	$ 152,779