Loans and Allowance for Credit Losses for Loans - Internal Loan Classification Risk by Loan Portfolio Class by Origination Year (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 50,311,702		$ 50,311,702		$ 50,210,295
Gross loan charge-offs
Total	38,339	$ 11,327	63,239	$ 43,900
Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	966,307		966,307		1,579,982
Year two, fiscal year before current fiscal year	1,155,531		1,155,531		1,123,368
Year three, two years before current fiscal year	911,279		911,279		784,426
Year four, three years before current fiscal year	647,694		647,694		379,097
Year five, four years before current fiscal year	317,003		317,003		217,248
More than five years before current fiscal year	653,810		653,810		588,062
Revolving Loans Amortized Cost Basis	4,797,152		4,797,152		4,524,198
Revolving Loans Converted to Term Loans	30,371		30,371		34,162
Total	9,479,147		9,479,147		9,230,543
Gross loan charge-offs
Total	14,721	3,865	29,014	29,912
Commercial and industrial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	935,588		935,588		1,494,417
Year two, fiscal year before current fiscal year	1,082,487		1,082,487		1,047,513
Year three, two years before current fiscal year	836,514		836,514		765,335
Year four, three years before current fiscal year	628,483		628,483		377,047
Year five, four years before current fiscal year	312,509		312,509		211,504
More than five years before current fiscal year	605,263		605,263		523,430
Revolving Loans Amortized Cost Basis	4,569,348		4,569,348		4,382,361
Revolving Loans Converted to Term Loans	10,703		10,703		29,798
Total	8,980,895		8,980,895		8,831,405
Commercial and industrial | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	1,569		1,569		70,807
Year two, fiscal year before current fiscal year	19,089		19,089		73,423
Year three, two years before current fiscal year	68,632		68,632		15,296
Year four, three years before current fiscal year	12,424		12,424		358
Year five, four years before current fiscal year	345		345		1,870
More than five years before current fiscal year	12,956		12,956		915
Revolving Loans Amortized Cost Basis	84,912		84,912		99,981
Revolving Loans Converted to Term Loans	487		487		139
Total	200,414		200,414		262,789
Commercial and industrial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	3,640		3,640		3,100
Year two, fiscal year before current fiscal year	47,951		47,951		1,837
Year three, two years before current fiscal year	6,118		6,118		2,629
Year four, three years before current fiscal year	5,859		5,859		1,714
Year five, four years before current fiscal year	3,494		3,494		1,221
More than five years before current fiscal year	7,633		7,633		5,900
Revolving Loans Amortized Cost Basis	136,764		136,764		29,569
Revolving Loans Converted to Term Loans	19,181		19,181		4,225
Total	230,640		230,640		50,195
Commercial and industrial | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	25,510		25,510		11,658
Year two, fiscal year before current fiscal year	6,004		6,004		595
Year three, two years before current fiscal year	15		15		1,166
Year four, three years before current fiscal year	928		928
Year four, three years before current fiscal year					(22)
Year five, four years before current fiscal year	655		655		2,653
More than five years before current fiscal year	27,958		27,958		57,817
Revolving Loans Amortized Cost Basis	6,128		6,128		12,287
Revolving Loans Converted to Term Loans	0		0		0
Total	67,198		67,198		86,154
Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total	31,768,846		31,768,846		31,970,047
Gross loan charge-offs
Total	22,356	$ 6,273	31,154	$ 11,971
Commercial real estate | Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	1,006,937		1,006,937		4,272,246
Year two, fiscal year before current fiscal year	4,115,631		4,115,631		6,738,948
Year three, two years before current fiscal year	6,569,888		6,569,888		5,052,212
Year four, three years before current fiscal year	4,863,314		4,863,314		3,022,501
Year five, four years before current fiscal year	2,895,051		2,895,051		2,469,773
More than five years before current fiscal year	7,787,687		7,787,687		5,957,963
Revolving Loans Amortized Cost Basis	863,117		863,117		622,497
Revolving Loans Converted to Term Loans	121,498		121,498		107,099
Total	28,223,123		28,223,123		28,243,239
Commercial real estate | Commercial real estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	968,014		968,014		4,088,835
Year two, fiscal year before current fiscal year	3,659,695		3,659,695		6,630,322
Year three, two years before current fiscal year	6,091,432		6,091,432		4,791,190
Year four, three years before current fiscal year	4,424,016		4,424,016		2,789,275
Year five, four years before current fiscal year	2,588,616		2,588,616		2,329,385
More than five years before current fiscal year	7,029,002		7,029,002		5,385,809
Revolving Loans Amortized Cost Basis	846,354		846,354		618,056
Revolving Loans Converted to Term Loans	121,498		121,498		104,839
Total	25,728,627		25,728,627		26,737,711
Commercial real estate | Commercial real estate | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	14,118		14,118		125,296
Year two, fiscal year before current fiscal year	268,022		268,022		82,917
Year three, two years before current fiscal year	229,614		229,614		248,900
Year four, three years before current fiscal year	170,904		170,904		184,720
Year five, four years before current fiscal year	73,508		73,508		69,949
More than five years before current fiscal year	352,075		352,075		358,059
Revolving Loans Amortized Cost Basis	14,721		14,721		26
Revolving Loans Converted to Term Loans	0		0		183
Total	1,122,962		1,122,962		1,070,050
Commercial real estate | Commercial real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	24,805		24,805		58,115
Year two, fiscal year before current fiscal year	187,914		187,914		25,709
Year three, two years before current fiscal year	248,842		248,842		12,122
Year four, three years before current fiscal year	268,394		268,394		48,506
Year five, four years before current fiscal year	232,927		232,927		70,439
More than five years before current fiscal year	406,610		406,610		214,095
Revolving Loans Amortized Cost Basis	2,042		2,042		4,415
Revolving Loans Converted to Term Loans	0		0		2,077
Total	1,371,534		1,371,534		435,478
Commercial real estate | Construction
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	343,144		343,144		760,480
Year two, fiscal year before current fiscal year	801,221		801,221		675,097
Year three, two years before current fiscal year	607,927		607,927		276,612
Year four, three years before current fiscal year	178,616		178,616		10,318
Year five, four years before current fiscal year	29,741		29,741		40,584
More than five years before current fiscal year	57,204		57,204		61,228
Revolving Loans Amortized Cost Basis	1,465,428		1,465,428		1,762,890
Revolving Loans Converted to Term Loans	62,442		62,442		139,599
Total	3,545,723		3,545,723		3,726,808
Commercial real estate | Construction | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	334,093		334,093		753,759
Year two, fiscal year before current fiscal year	794,473		794,473		655,198
Year three, two years before current fiscal year	594,972		594,972		267,336
Year four, three years before current fiscal year	169,683		169,683		10,318
Year five, four years before current fiscal year	22,469		22,469		40,584
More than five years before current fiscal year	45,294		45,294		43,560
Revolving Loans Amortized Cost Basis	1,366,676		1,366,676		1,762,890
Revolving Loans Converted to Term Loans	62,442		62,442		139,599
Total	3,390,102		3,390,102		3,673,244
Commercial real estate | Construction | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	9,051		9,051
Year two, fiscal year before current fiscal year	0		0
Year three, two years before current fiscal year	0		0
Year four, three years before current fiscal year	0		0
Year five, four years before current fiscal year	0		0
More than five years before current fiscal year	0		0
Revolving Loans Amortized Cost Basis	19,767		19,767
Revolving Loans Converted to Term Loans	0		0
Total	28,818		28,818
Commercial real estate | Construction | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	0		0		6,721
Year two, fiscal year before current fiscal year	6,748		6,748		0
Year three, two years before current fiscal year	0		0		9,276
Year four, three years before current fiscal year	8,933		8,933		0
Year five, four years before current fiscal year	0		0		0
More than five years before current fiscal year	0		0		17,668
Revolving Loans Amortized Cost Basis	78,985		78,985		0
Revolving Loans Converted to Term Loans	0		0		0
Total	94,666		94,666		33,665
Commercial real estate | Construction | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, current fiscal year	0		0		0
Year two, fiscal year before current fiscal year	0		0		19,899
Year three, two years before current fiscal year	12,955		12,955		0
Year four, three years before current fiscal year	0		0		0
Year five, four years before current fiscal year	7,272		7,272		0
More than five years before current fiscal year	11,910		11,910		0
Revolving Loans Amortized Cost Basis	0		0		0
Revolving Loans Converted to Term Loans	0		0		0
Total	$ 32,137		32,137		19,899
Commercial and Industrial and Commercial Real Estate
Gross loan charge-offs
Year one, gross loan charge-offs			0		307
Year two, gross loan charge-offs			2,106		12,919
Year three, gross loan charge-offs			3,177		28,438
Year four, gross loan charge-offs			21,351		6,946
Year five, gross loan charge-offs			11,061		5,031
More than five years gross loan charge-offs			17,219		13,446
Revolving Loans Amortized Cost Basis			3,930		3,729
Revolving Loans Converted to Term Loans			1,324		145
Total			$ 60,168		$ 70,961