Business Segment Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Segment Reporting Information [Line Items]
Net interest income	$ 80,365	$ 79,074	$ 239,827	$ 237,440
Provision for loan losses	4,500	4,500	13,500	17,200
Noninterest income	106,321	100,957	348,848	316,563
Noninterest expense	145,905	139,428	432,495	420,525
Income before income taxes	36,281	36,103	142,680	116,278
Income tax expense	10,156	10,088	41,023	33,072
Net income	26,125	26,015	101,657	83,206
Average assets	13,172,000	12,157,000	13,224,000	12,374,000
Bank
Segment Reporting Information [Line Items]
Net interest income	69,109	67,773	206,611	204,368
Provision for loan losses	2,168	1,873	6,424	8,849
Noninterest income	47,851	48,386	168,885	158,049
Noninterest expense	94,012	92,768	282,142	281,643
Income before income taxes	20,780	21,518	86,930	71,925
Income tax expense	5,320	5,818	23,772	19,418
Net income	15,460	15,700	63,158	52,507
Average assets	10,681,000	10,360,000	10,850,000	10,235,000
Payment Solutions
Segment Reporting Information [Line Items]
Net interest income	10,843	10,832	32,124	31,687
Provision for loan losses	2,332	2,627	7,076	8,351
Noninterest income	15,381	14,004	48,122	41,757
Noninterest expense	17,696	13,199	49,030	41,135
Income before income taxes	6,196	9,010	24,140	23,958
Income tax expense	2,060	2,634	7,544	7,394
Net income	4,136	6,376	16,596	16,564
Average assets	849,000	745,000	855,000	692,000
Institutional Investment Management
Segment Reporting Information [Line Items]
Net interest income		3	2	9
Noninterest income	24,789	21,593	74,585	64,156
Noninterest expense	17,186	16,792	50,375	49,337
Income before income taxes	7,603	4,804	24,212	14,828
Income tax expense	2,130	1,340	6,974	4,217
Net income	5,473	3,464	17,238	10,611
Average assets	80,000	93,000	82,000	89,000
Asset Servicing
Segment Reporting Information [Line Items]
Net interest income	413	466	1,090	1,376
Noninterest income	18,300	16,974	57,256	52,601
Noninterest expense	17,011	16,669	50,948	48,410
Income before income taxes	1,702	771	7,398	5,567
Income tax expense	646	296	2,733	2,043
Net income	1,056	475	4,665	3,524
Average assets	$ 1,562,000	$ 959,000	$ 1,437,000	$ 1,358,000