CONSOLIDATED STATEMENTS OF CASH FLOW - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net income	$ 81,461	$ 92,015	$ 82,414
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	36,001	15,833	19,462
Depreciation of premises and equipment	5,673	5,786	5,620
Stock-based compensation	3,293	2,765	3,553
Amortization of investment securities premiums and accretion of discounts, net	6,057	4,014	3,477
Amortization of mortgage servicing rights	2,361	1,312	956
Mortgage servicing rights impairments	812	0	0
Amortization of right of use assets	2,842	3,046	0
Deferred income taxes	(24,160)	(5,730)	(550)
(Gains) losses on investment securities available-for-sale	(279)	0	345
Originations of loans held for sale, net of principal collected	(330,990)	(145,097)	(78,450)
Proceeds from the sales of loans held for sale	351,337	139,050	82,127
Net gains on sale of loans held for sale	(12,955)	(2,940)	(1,844)
Net gains on sale of other real estate and repossessions	(138)	(487)	(561)
Net gain on sale of premises and equipment	0	(1,251)	(128)
Change in interest receivable	(1,117)	(245)	(1,747)
Change in interest payable	(9,923)	4,968	2,997
Change in other assets	12,782	11,213	(7,048)
Change in other liabilities	10,293	13,492	21,884
Other	940	1,734	940
Net change in operating activities	154,493	164,606	159,695
Investing activities:
Proceeds from sales of investment securities available-for-sale	8,403	0	11,392
Proceeds from maturities and paydowns of investment securities available-for-sale	443,617	317,295	145,167
Purchases of investment securities available-for-sale	(597,296)	(351,189)	(255,205)
Net change in partnership investments	(54,981)	(33,840)	(13,669)
Net change in other investments	985	(10)	(2,451)
Loans sold or participated to others	17,462	53,369	22,835
Proceeds from principal payments on direct finance leases	54,771	69,188	50,457
Net change in loans and leases	(489,477)	(392,475)	(405,961)
Net change in equipment owned under operating leases	26,414	(2,495)	(21,107)
Purchases of premises and equipment	(2,850)	(8,033)	(3,058)
Proceeds from disposal of premises and equipment	23	3,418	216
Proceeds from sales of other real estate and repossessions	10,271	10,855	13,433
Net change in investing activities	(582,658)	(333,917)	(457,951)
Financing activities:
Net change in demand deposits and savings accounts	1,069,843	54,272	171,799
Net change in time deposits	(481,141)	180,732	197,793
Net change in short-term borrowings	4,748	(53,451)	(15,251)
Proceeds from issuance of long-term debt	10,000	0	0
Payments on long-term debt	(2,905)	(2,695)	(1,735)
Stock issued under stock purchase plans	39	49	145
Acquisition of treasury stock	(6,415)	(15,085)	(9,271)
Net change in noncontrolling interests	23,442	18,796	1,508
Cash dividends paid on common stock	(29,764)	(29,021)	(25,686)
Net change in financing activities	587,847	153,597	319,302
Net change in cash and cash equivalents	159,682	(15,714)	21,046
Cash and cash equivalents, beginning of year	83,365	99,079	78,033
Cash and cash equivalents, end of year	243,047	83,365	99,079
Leased equipment
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	$ 20,203	$ 25,128	$ 26,248