Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating Activities
Net income	$ 49,132	$ 38,559
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	57	795
Net amortization of debt securities	5,379	3,465
Net (accretion) amortization of purchase accounting adjustments	(1,788)	1,337
Amortization of debt modification costs	412	412
Origination of loans held for sale	(145,163)	(175,506)
Proceeds from loans held for sale	154,756	184,188
Gain on sale of loans	(5,798)	(6,097)
(Gain) loss on sale of debt securities	(213)	333
Bank-owned life insurance income, net	(497)	(424)
Stock-based compensation, net of tax benefits	1,197	1,189
Depreciation and amortization of premises and equipment	4,574	3,722
Gain on sale and write-downs of other real estate owned, net	(416)	(53)
Amortization of core deposit intangibles	1,694	1,056
Amortization of investments in variable interest entities	1,644	1,117
Net increase in accrued interest receivable	(2,959)	(2,709)
Net (increase) decrease in other assets	(1,636)	289
Net increase (decrease) in accrued interest payable	457	(155)
Net decrease in other liabilities	(14,525)	(3,582)
Net cash provided by operating activities	46,307	47,936
Investing Activities
Sales of available-for-sale debt securities	269,616	219,855
Maturities, prepayments and calls of available-for-sale debt securities	120,368	72,952
Purchases of available-for-sale debt securities	(311,281)	(383,992)
Maturities, prepayments and calls of held-to-maturity debt securities	29,945	13,297
Principal collected on loans	617,236	552,922
Loan originations	(656,930)	(678,251)
Net additions to premises and equipment	(3,809)	(5,558)
Proceeds from sale of other real estate owned	1,208	755
Proceeds from redemption of non-marketable equity securities	39,436	28,986
Purchases of non-marketable equity securities	(28,000)	(18,395)
Investments in variable interest entities	(576)	(16,129)
Net cash received from acquisitions	0	101,268
Net cash provided by (used in) investing activities	77,213	(112,290)
Financing Activities
Net increase in deposits	94,322	524,162
Net increase in securities sold under agreements to repurchase	93,470	4,041
Net decrease in short-term Federal Home Loan Bank advances	(285,000)	(200,000)
Repayments of long-term Federal Home Loan Bank advances	(896)	(104)
Net increase (decrease) in other borrowed funds	27	(11,562)
Cash dividends paid	(25,562)	(107)
Tax withholding payments for stock-based compensation	(1,144)	(1,032)
Net cash (used in) provided by financing activities	(124,783)	315,398
Net (decrease) increase in cash, cash equivalents and restricted cash	(1,263)	251,044
Cash, cash equivalents and restricted cash at beginning of period	203,790	200,004
Cash, cash equivalents and restricted cash at end of period	202,527	451,048
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest	10,447	7,930
Supplemental Disclosure of Non-Cash Investing and Financing Activities
Transfer of loans to other real estate owned	1,437	378
Right-of-use assets obtained in exchange for operating lease liabilities	647	0
Dividends declared but not paid	22,039	19,476
Fair value of common stock shares issued	0	250,807
Cash consideration for outstanding shares	0	16,265
Effective settlement of a pre-existing relationship	0	10,054
Fair Value of Assets Acquired	0	1,549,158
Liabilities Assumed	$ 0	$ 1,383,756