Consolidated Statements of Cash Flows $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)		Dec. 31, 2015 USD ($)		Dec. 31, 2014 USD ($)
Operating Activities
Net income	$ 121,131		$ 116,127		$ 112,755
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	2,333		2,284		1,912
Net amortization of investment securities premiums and discounts	26,210		26,709		27,491
Loans held for sale originated or acquired	(1,098,864)		(888,676)		(669,144)
Proceeds from sales of loans held for sale	1,155,186		925,353		705,178
Gain on sale of loans	(33,606)		(26,389)		(19,797)
Loss (gain) on sale of investments	1,463		(19)		188
Bargain purchase gain	0		0		(680)
Stock-based compensation expense, net of tax benefits	1,836		1,087		859
Excess tax benefits from stock-based compensation	(8)		(102)		(138)
Depreciation of premises and equipment	15,294		14,365		12,108
Loss (gain) on sale of other real estate owned and write-downs, net	1,217		938		(937)
Core deposit intangible amortization	2,970		2,964		2,811
Deferred tax (benefit) expense	(82)	[1]	(4,080)	[1]	5,931	[1]
Amortization of qualified affordable housing project investments	1,079		1,175		1,270
Amortization of New Markets Tax Credit project investments	1,453		2,323		1,893
Net (increase) decrease in accrued interest receivable	(1,160)		(2,377)		2,648
Net increase in other assets	(9,494)		(793)		(5,702)
Net increase (decrease) in accrued interest payable	55		(828)		567
Net (decrease) increase in other liabilities	(6,611)		1,405		3,521
Net cash provided by operating activities	180,402		171,466		182,734
Investing Activities
Sales of available-for-sale securities	62,817		136,777		169,372
Maturities, prepayments and calls of available-for-sale securities	662,003		663,828		628,238
Purchases of available-for-sale securities	(585,064)		(961,224)		(281,332)
Maturities, prepayments and calls of held-to-maturity securities	25,405		20,997		8,930
Purchases of held-to-maturity securities	(1,222)		(203,554)		(49,691)
Principal collected on loans	1,775,173		1,737,508		1,418,517
Loans originated or acquired	(2,375,136)		(2,112,154)		(1,735,155)
Net decrease (increase) of premises and equipment and other real estate owned	5,197		(18,224)		(14,389)
Proceeds from sale of other real estate owned	10,145		10,278		15,714
Net proceeds from sale of non-marketable equity securities	6,017		27,770		801
Net cash received (paid) in acquisitions	6,701		21,427		(2,112)
Net cash (used in) provided by investing activities	(407,964)		(676,571)		158,893
Financing Activities
Net increase in deposits	368,907		215,650		455,604
Net increase in securities sold under agreements to repurchase	50,236		24,951		83,713
Net (decrease) increase in short-term Federal Home Loan Bank advances	(100,000)		140,000		(421,000)
Proceeds from long-term Federal Home Loan Bank advances	0		50,000		192,500
Repayments of long-term Federal Home Loan Bank advances	(45,642)		(94,749)		(314,738)
Net decrease in other borrowed funds	(2,019)		(566)		(933)
Cash dividends paid	(84,040)		(79,456)		(50,944)
Excess tax benefits from stock-based compensation	8		102		138
Stock-based compensation activity	(600)		17		785
Net cash provided by (used in) financing activities	186,850		255,949		(54,875)
Net (decrease) increase in cash and cash equivalents	(40,712)		(249,156)		286,752
Cash and cash equivalents at beginning of period	193,253		442,409		155,657
Cash and cash equivalents at end of period	152,541		193,253		442,409
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest	29,576		30,103		26,398
Cash paid during the period for income taxes	36,225		39,622		33,343
Supplemental Disclosure of Non-Cash Investing Activities
Transfer of investment securities from available-for-sale to held-to-maturity	0		0		484,583
Sale and refinancing of other real estate owned	728		446		1,361
Transfer of loans to other real estate owned	5,198		7,989		11,493
Dividend declared but not paid	23,137		22,893		22,557
Fair value of common stock shares issued	10,465		25,939		15,127
Cash consideration for outstanding shares	3,475		28,364		16,690
Fair value of assets acquired	69,750		434,963		349,167
Liabilities assumed	$ 62,225		$ 391,592		$ 316,670

[1] Includes tax benefit of operating loss carryforwards of $571,000, $391,000 and $0 for the years ended December 31, 2016, 2015, and 2014, respectively.