Consolidated Statement of income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
INTEREST AND DIVIDEND INCOME
Loans receivable, including fees	$ 1,198,440	$ 1,035,377	$ 968,625
Investment securities	58,670	53,399	41,375
Resale agreements	32,095	30,547	19,799
Restricted equity securities	2,524	3,427	6,077
Interest-bearing cash and deposits with banks	33,390	14,731	17,939
Total interest and dividend income	1,325,119	1,137,481	1,053,815
INTEREST EXPENSE
Deposits	116,391	84,224	73,505
Federal funds purchased and other short-term borrowings	1,003	713	58
FHLB advances	7,751	5,585	4,270
Repurchase agreements	9,476	9,304	20,907
Long-term debt	5,429	5,017	4,636
Total interest expense	140,050	104,843	103,376
Net interest income before provision for credit losses	1,185,069	1,032,638	950,439
Provision for credit losses	46,266	27,479	14,217
Net interest income after provision for credit losses	1,138,803	1,005,159	936,222
NONINTEREST INCOME
Branch fees	42,490	41,178	39,495
Letters of credit fees and foreign exchange income	42,779	45,760	38,985
Ancillary loan fees and other income	23,333	19,352	15,029
Wealth management fees	14,632	13,240	18,268
Derivative fees and other income	17,671	16,781	16,493
Net gains on sales of loans	8,870	6,085	24,873
Net gains on sales of available-for-sale investment securities	8,037	10,362	40,367
Net gains on sales of fixed assets	77,388	3,178	3,567
Net gain on sale of business	3,807	0	0
Changes in Federal Deposit Insurance Corporation (“FDIC”) indemnification asset and receivable/payable	0	0	(37,980)
Other fees and operating income	19,399	26,982	24,286
Total noninterest income	258,406	182,918	183,383
NONINTEREST EXPENSE
Compensation and employee benefits	335,291	300,115	262,193
Occupancy and equipment expense	64,921	61,453	61,292
Deposit insurance premiums and regulatory assessments	23,735	23,279	18,772
Legal expense	11,444	2,841	16,373
Data processing	12,093	11,683	10,185
Consulting expense	14,922	22,742	17,234
Deposit related expense	9,938	10,394	10,379
Computer software expense	18,183	12,914	8,660
Other operating expense	76,697	78,936	68,624
Amortization of tax credit and other investments	87,950	83,446	36,120
Amortization of core deposit intangibles	6,935	8,086	9,234
Repurchase agreements’ extinguishment costs	0	0	21,818
Total noninterest expense	662,109	615,889	540,884
INCOME BEFORE INCOME TAXES	735,100	572,188	578,721
INCOME TAX EXPENSE	229,476	140,511	194,044
NET INCOME	$ 505,624	$ 431,677	$ 384,677
EARNINGS PER SHARE (“EPS”)
BASIC (in dollars per share)	$ 3.50	$ 3.00	$ 2.67
DILUTED (in dollars per share)	$ 3.47	$ 2.97	$ 2.66
WEIGHTED-AVERAGE NUMBER OF SHARES OUTSTANDING
BASIC (in shares)	144,444	144,087	143,818
DILUTED (in shares)	145,913	145,172	144,512
CASH DIVIDENDS DECLARED PER COMMON SHARE (in dollars per share)	$ 0.8	$ 0.8	$ 0.8