Line of Business Segment Financial Results (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Net interest income	$ 80,229	$ 80,365	$ 80,373	$ 79,089	$ 79,533	$ 79,074	$ 79,918	$ 78,448	$ 320,056	$ 316,973	$ 310,613
Provision for loan losses	(4,000)	(4,500)	(4,500)	(4,500)	(5,000)	(4,500)	(5,600)	(7,100)	17,500	22,200	31,510
Noninterest income	109,274	106,321	110,226	132,301	97,769	100,957	107,856	107,750	458,122	414,332	360,370
Noninterest expense	157,959	145,905	144,686	141,904	142,221	139,428	145,581	135,516	590,454	562,746	512,622
Income before income taxes									170,224	146,359	126,851
Income tax expense	(6,484)	(10,156)	(12,248)	(18,619)	(6,815)	(10,088)	(10,272)	(12,712)	47,507	39,887	35,849
Net income	21,060	26,125	29,165	46,367	23,266	26,015	26,321	30,870	122,717	106,472	91,002
Average assets	13,389,000				12,417,000				13,389,000	12,417,000	11,108,000
Bank
Segment Reporting Information [Line Items]
Net interest income									275,178	273,481	269,318
Provision for loan losses									8,098	11,060	17,229
Noninterest income									216,688	205,877	187,304
Noninterest expense									383,034	378,065	352,512
Income before income taxes									100,734	90,233	86,881
Income tax expense									26,533	23,085	24,937
Net income									74,201	67,148	61,944
Average assets	10,949,000				10,336,000				10,949,000	10,336,000	9,410,000
Payment Solutions
Segment Reporting Information [Line Items]
Net interest income									43,351	42,101	39,856
Provision for loan losses									9,402	11,140	14,281
Noninterest income									65,723	54,702	47,481
Noninterest expense									68,903	56,367	50,554
Income before income taxes									30,769	29,296	22,502
Income tax expense									9,430	9,002	5,682
Net income									21,339	20,294	16,820
Average assets	876,000				717,000				876,000	717,000	554,000
Institutional Investment Management
Segment Reporting Information [Line Items]
Net interest income									2	45
Noninterest income									100,093	83,955	60,987
Noninterest expense									70,527	64,050	50,034
Income before income taxes									29,568	19,950	10,953
Income tax expense									8,269	5,534	2,888
Net income									21,299	14,416	8,065
Average assets	82,000				90,000				82,000	90,000	51,000
Asset Servicing
Segment Reporting Information [Line Items]
Net interest income									1,525	1,346	1,439
Noninterest income									75,618	69,798	64,598
Noninterest expense									67,990	64,264	59,522
Income before income taxes									9,153	6,880	6,515
Income tax expense									3,275	2,266	2,342
Net income									5,878	4,614	4,173
Average assets	$ 1,482,000				$ 1,274,000				$ 1,482,000	$ 1,274,000	$ 1,093,000