Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Operating Activities
Net income	$ 158,429	$ 106,783
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	(5,605)	36,114
Net amortization of debt securities	19,615	6,831
Net amortization of purchase accounting adjustments and deferred loan fees and costs	4,113	33,329
Origination of loans held for sale	(827,653)	(847,288)
Proceeds from loans held for sale	976,517	849,626
Gain on sale of loans	(37,730)	(37,720)
Gain on sale of debt securities	(223)	(991)
Bank-owned life insurance income, net	(1,352)	(1,356)
Stock-based compensation, net of tax benefits	2,408	1,994
Depreciation and amortization of premises and equipment	10,446	9,907
Gain on sale and write-downs of other real estate owned, net	(247)	(169)
Amortization of core deposit intangibles	4,976	5,146
Amortization of investments in variable interest entities	6,474	4,973
Net decrease (increase) in accrued interest receivable	5,045	(19,529)
Net increase in other assets	(13,239)	(15,048)
Net decrease in accrued interest payable	(11,017)	(602)
Net (decrease) increase in other liabilities	(872)	5,174
Net cash provided by operating activities	290,085	137,174
Investing Activities
Maturities, prepayments and calls of available-for-sale debt securities	611,077	341,724
Purchases of available-for-sale debt securities	(2,351,093)	(1,042,423)
Maturities, prepayments and calls of held-to-maturity debt securities	6,360	20,250
Principal collected on loans	3,281,147	1,835,968
Loan originations	(3,446,582)	(3,371,733)
Net disposals (additions) to premises and equipment	1,435	(4,861)
Proceeds from sale of other real estate owned	2,679	1,523
Proceeds from redemption of non-marketable equity securities	3	75,049
Purchases of non-marketable equity securities	0	(71,398)
Proceeds from bank-owned life insurance	2,112	0
Investments in variable interest entities	(10,711)	(7,321)
Net cash received from acquisitions	0	43,713
Net cash used in investing activities	(1,903,573)	(2,179,509)
Financing Activities
Net increase in deposits	1,963,419	2,001,950
Net (decrease) increase in securities sold under agreements to repurchase	(9,382)	304,154
Net decrease in short-term Federal Home Loan Bank advances	0	(30,000)
Proceeds from long-term Federal Home Loan Bank advances	0	30,000
Repayments of long-term Federal Home Loan Bank advances	0	(631)
Net (increase) decrease in other borrowed funds	(7,012)	43
Cash dividends paid	(44,142)	(46,324)
Tax withholding payments for stock-based compensation	(1,495)	(1,003)
Proceeds from stock option exercises	165	795
Net cash provided by financing activities	1,901,553	2,258,984
Net increase in cash, cash equivalents and restricted cash	288,065	216,649
Cash, cash equivalents and restricted cash at beginning of period	633,142	330,961
Cash, cash equivalents and restricted cash at end of period	921,207	547,610
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest	10,099	16,282
Cash paid during the period for income taxes	49,663	8,550
Supplemental Disclosure of Non-Cash Investing and Financing Activities
Transfer of debt securities from available-for-sale to held-to-maturity	844,020	0
Sale and refinancing of other real estate owned	0	215
Transfer of loans to other real estate owned	1,459	791
Right-of-use assets obtained in exchange for operating lease liabilities	720	5,253
Dividends declared during the period but not paid	30,697	27,785
Acquisitions
Fair value of common stock shares issued	0	112,133
Cash consideration	0	13,721
Fair value of assets acquired	0	745,420
Liabilities assumed	$ 0	$ 619,566