CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
OPERATING ACTIVITIES:
Net income	$ 65,931	$ 60,546
Adjustments to reconcile net income to net cash provided by operating activities:
Net amortization on investment securities	(95)	(204)
Net accretion on loans and amortization of core deposit intangible and operating lease components	(2,622)	(2,744)
Unrealized (gains) losses on equity securities with readily determinable fair value	(561)	211
Depreciation of premises and equipment	6,989	7,020
Amortization of mortgage servicing rights	1,275	1,092
Provision for loan and lease losses	24,844	26,264
Net gain on sale of mortgage loans held for sale	(6,452)	(2,985)
Origination of mortgage loans held for sale	(247,071)	(133,273)
Proceeds from sale of mortgage loans held for sale	229,755	134,157
Net gain on sale of consumer loans held for sale	(3,869)	(4,429)
Origination of consumer loans held for sale	(534,268)	(582,871)
Proceeds from sale of consumer loans held for sale	532,471	576,646
Net gain realized on sale of other real estate owned	(487)	(700)
Impairment of premises held for sale	198	356
Deferred compensation expense - Class A Common Stock	457	449
Stock-based awards expense - Class A Common Stock	883	730
Increase in cash surrender value of bank owned life insurance	(1,154)	(1,135)
Net change in other assets and liabilities:
Accrued interest receivable	269	(1,614)
Accrued interest payable	1,278	6
Other assets	(6,011)	2,314
Other liabilities	(1,836)	5,870
Net cash provided by operating activities	59,924	85,706
INVESTING ACTIVITIES:
Purchases of available-for-sale debt securities	(350,036)	(159,880)
Purchases of held-to-maturity debt securities		(4,934)
Proceeds from calls, maturities and paydowns of available-for-sale debt securities	259,569	236,138
Proceeds from calls, maturities and paydowns of held-to-maturity debt securities	1,897	3,213
Net change in outstanding warehouse lines of credit	(504,893)	(35,242)
Net change in other loans	(163,133)	(108,750)
Proceeds from redemption of Federal Home Loan Bank stock	2,102
Purchase of Federal Home Loan Bank stock	(2,277)
Proceeds from sales of other real estate owned	1,892	1,153
Net purchases of premises and equipment	(9,102)	(7,716)
Net cash used in investing activities	(763,981)	(76,018)
FINANCING ACTIVITIES:
Net change in deposits	420,991	133,527
Net change in securities sold under agreements to repurchase and other short-term borrowings	(15,041)	(40,253)
Payments of Federal Home Loan Bank advances	(590,000)	(417,500)
Proceeds from Federal Home Loan Bank advances	950,000	395,000
Repurchase of Class A Common Stock	(580)
Net proceeds from Class A Common Stock purchased through employee stock purchase plan	372	124
Net proceeds from Class A Common Stock options exercised	(174)	83
Cash dividends paid	(15,913)	(14,508)
Net cash provided by financing activities	749,655	56,473
NET CHANGE IN CASH AND CASH EQUIVALENTS	45,598	66,161
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	351,474	299,351
CASH AND CASH EQUIVALENTS AT END OF PERIOD	397,072	365,512
Cash paid during the period for:
Interest	33,348	21,491
Income taxes	11,506	10,196
SUPPLEMENTAL NONCASH DISCLOSURES:
Transfers from loans to real estate acquired in settlement of loans	1,414	408
Transfers from loans held for sale to held for investment		2,237
Transfers from loans held for investment to held for sale	130,770	1,392
Unfunded commitments in low-income-housing investments		$ 12,574
Right-of-use assets recorded upon adoption of ASU 2016-02	$ 41,726