CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
OPERATING ACTIVITIES:
Net income	$ 60,546	$ 40,794
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization (accretion) on investment securities, net	(204)	231
Accretion on loans and amortization of core deposit intangible, net	(2,744)	(3,981)
Unrealized losses on equity securities with readily determinable fair value	211
Depreciation of premises and equipment	7,020	6,178
Amortization of mortgage servicing rights	1,092	1,104
Provision for loan and lease losses	26,264	21,633
Net gain on sale of mortgage loans held for sale	(2,985)	(3,221)
Origination of mortgage loans held for sale	(133,273)	(119,265)
Proceeds from sale of mortgage loans held for sale	134,157	130,065
Net gain on sale of consumer loans held for sale	(4,429)	(3,869)
Origination of consumer loans held for sale	(582,871)	(454,844)
Proceeds from sale of consumer loans held for sale	576,646	453,169
Net gain realized on sale of other real estate owned	(700)	(577)
Writedowns of other real estate owned		155
Impairment of premises held for sale	356	1,082
Deferred compensation expense - Class A Common Stock	449	147
Stock-based awards expense - Class A Common Stock	730	928
Increase in cash surrender value of bank owned life insurance	(1,135)	(1,178)
Net change in other assets and liabilities:
Accrued interest receivable	(1,614)	(1,001)
Accrued interest payable	6	(12)
Other assets	2,314	(3,367)
Other liabilities	5,870	3,283
Net cash provided by operating activities	85,706	67,454
INVESTING ACTIVITIES:
Purchases of available-for-sale debt securities	(159,880)	(91,451)
Purchases of held-to-maturity debt securities	(4,934)	(15,460)
Proceeds from calls, maturities and paydowns of available-for-sale debt securities	236,138	114,930
Proceeds from calls, maturities and paydowns of held-to-maturity debt securities	3,213	3,129
Net change in outstanding warehouse lines of credit	(35,242)	14,279
Purchase of non-business-acquisition loans, including premiums paid		(4,811)
Net change in other loans	(108,750)	(166,845)
Purchase of Federal Home Loan Bank stock		(3,859)
Proceeds from sales of other real estate owned	1,153	2,202
Net purchases of premises and equipment	(7,716)	(9,236)
Net cash used in investing activities	(76,018)	(157,122)
FINANCING ACTIVITIES:
Net change in deposits	133,527	189,037
Net change in securities sold under agreements to repurchase and other short-term borrowings	(40,253)	(162)
Payments of Federal Home Loan Bank advances	(417,500)	(460,000)
Proceeds from Federal Home Loan Bank advances	395,000	415,000
Repurchase of Class A Common Stock		(558)
Net proceeds from Class A Common Stock purchased through employee stock purchase plan	124
Net proceeds from Class A Common Stock options exercised	83	33
Cash dividends paid	(14,508)	(13,129)
Net cash used in financing activities	56,473	130,221
NET CHANGE IN CASH AND CASH EQUIVALENTS	66,161	40,553
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	299,351	289,309
CASH AND CASH EQUIVALENTS AT END OF PERIOD	365,512	329,862
Cash paid during the period for:
Interest	21,491	14,559
Income taxes	10,196	20,570
SUPPLEMENTAL NONCASH DISCLOSURES:
Transfers from loans to real estate acquired in settlement of loans	408	$ 556
Transfers from loans held for sale to held for investment	2,237
Unfunded commitments in low-income housing investments	$ 12,574