Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Interest income:
Loans	$ 610,945		$ 542,204		$ 469,146
Investment securities:
Taxable	271,371		180,162		171,863
Non-taxable	3,136		3,201		3,564
Federal funds sold, securities purchased under agreements to resell and other short-term investment securities	6,464		4,054		4,145
Total interest income	891,916		729,621		648,718
Interest expense:
Deposits	12,114		9,128		6,660
Borrowings	23,207		23,149		24,194
Total interest expense	35,321		32,277		30,854
Net interest income	856,595		697,344		617,864
Provision for loan losses	59,486		63,693		44,330
Net interest income after provision for loan losses	797,109		633,651		573,534
Noninterest income:
Gains on investment securities, net	267,023		419,408		122,114
Foreign exchange fees	71,659		57,411		52,433
Gains on derivative instruments, net	96,845		42,184		18,679
Deposit service charges	39,937		35,948		33,421
Credit card fees	41,792		32,461		24,809
Lending related fees	25,711		20,980		18,038
Letters of credit and standby letters of credit fees	15,649		14,716		15,150
Client investment fees	14,883		13,959		14,539
Other	(1,260)		36,139		36,363
Total noninterest income	572,239		673,206		335,546
Noninterest expense:
Compensation and benefits	409,486		366,801		326,942
Professional services	94,377		76,178		67,845
Premises and equipment	49,716		45,935		40,689
Business development and travel	40,057		33,334		29,409
Net occupancy	30,004		24,937		22,536
FDIC assessments	19,206		12,784		10,959
Correspondent bank fees	13,118		12,142		11,168
Provision for unfunded credit commitments	6,511		7,642		488
Other	54,396		41,927		35,962
Total noninterest expense	716,871	[1]	621,680	[1]	545,998	[1]
Income before income tax expense	652,477	[2]	685,177	[2]	363,082	[2]
Income tax expense	173,762		139,058		113,269
Net income before noncontrolling interests	478,715		546,119		249,813
Net income attributable to noncontrolling interests	(214,790)		(330,266)		(74,710)
Net income available to common stockholders	$ 263,925		$ 215,853		$ 175,103
Earnings per common share—basic, in dollars per share	$ 5.39		$ 4.76		$ 3.96
Earnings per common share—diluted, in dollars per share	$ 5.31		$ 4.70		$ 3.91

[1] The Global Commercial Bank segment includes direct depreciation and amortization of $20.9 million, $18.7 million and $14.4 million for 2014, 2013 and 2012, respectively.

[2] The internal reporting model used by management to assess segment performance does not calculate income tax expense by segment. Our effective tax rate is a reasonable approximation of the segment rates.