Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Operating Activities
Net income	$ 153,134	$ 132,279
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	57	8,707
Net amortization of debt securities	11,687	10,088
Net accretion of purchase accounting adjustments	(2,680)	(2,962)
Amortization of debt modification costs	4,630	1,237
Origination of loans held for sale	(671,038)	(647,932)
Proceeds from loans held for sale	633,085	669,344
Gain on sale of loans	(23,929)	(21,495)
(Gain) loss on sale of debt securities	(14,158)	756
Bank-owned life insurance income, net	(1,629)	(1,782)
Stock-based compensation, net of tax benefits	6,554	2,523
Depreciation and amortization of premises and equipment	13,713	11,543
(Gain) loss on sale and write-downs of other real estate owned, net	(288)	2,347
Amortization of core deposit intangibles	5,919	4,539
Amortization of investments in variable interest entities	6,767	5,070
Net increase in accrued interest receivable	(5,348)	(10,581)
Net increase in other assets	(367)	(6,820)
Net increase in accrued interest payable	61	170
Net (decrease) increase in other liabilities	(1,730)	10,481
Net cash provided by operating activities	114,440	167,512
Investing Activities
Sales of available-for-sale debt securities	711,268	224,612
Maturities, prepayments and calls of available-for-sale debt securities	457,299	259,102
Purchases of available-for-sale debt securities	(839,835)	(550,096)
Maturities, prepayments and calls of held-to-maturity debt securities	48,940	55,202
Principal collected on loans	2,497,073	1,908,670
Loan originations	(2,900,692)	(2,500,098)
Net additions to premises and equipment	(14,230)	(13,984)
Proceeds from sale of other real estate owned	2,960	3,370
Proceeds from redemption of non-marketable equity securities	115,436	73,199
Purchases of non-marketable equity securities	(93,397)	(62,585)
Proceeds from bank-owned life insurance	0	1,331
Investments in variable interest entities	(7,956)	(30,685)
Net cash received from acquisitions	79,334	101,268
Net cash provided by (used in) investing activities	56,200	(530,694)
Financing Activities
Net increase in deposits	377,986	706,469
Net increase in securities sold under agreements to repurchase	161,191	17,001
Net decrease in short-term Federal Home Loan Bank advances	(285,000)	(200,000)
Repayments of long-term Federal Home Loan Bank advances	(151,073)	(641)
Net increase (decrease) in other borrowed funds	97	(9,823)
Cash dividends paid	(70,970)	(41,542)
Tax withholding payments for stock-based compensation	(277)	(1,182)
Net cash provided by financing activities	31,954	470,282
Net increase in cash, cash equivalents and restricted cash	202,594	107,100
Cash, cash equivalents and restricted cash at beginning of period	203,790	200,004
Cash, cash equivalents and restricted cash at end of period	406,384	307,104
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest	33,878	25,925
Cash paid during the period for income taxes	33,032	18,440
Supplemental Disclosure of Non-Cash Investing and Financing Activities
Sale and refinancing of other real estate owned	7	406
Transfer of loans to other real estate owned	2,347	4,066
Right-of-use assets obtained in exchange for operating lease liabilities	3,910	0
Dividends declared but not paid	26,874	22,240
Fair value of common stock shares issued	316,538	250,807
Cash consideration	16,424	16,265
Effective settlement of a pre-existing relationship	0	10,054
Fair Value of Assets Acquired	1,190,267	1,549,158
Liabilities Assumed	$ 1,024,141	$ 1,383,756