Segment Results (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Segment Reporting Information [Line Items]
Net interest income	$ 1,166,616		$ 1,160,021		$ 1,200,421
Provisions for loan losses	30,758		62,988		100,420
Non-Interest Income	218,830		297,353		235,325
Non-interest expense	607,562	[1]	613,477	[1]	600,749
Income before income taxes	747,126		780,909		734,577
Income tax expense	271,579		279,803		254,540
Net income	475,547		501,106		480,037
Identifiable segment assets (period-end)	46,688,287		44,145,100
Third Party
Segment Reporting Information [Line Items]
Non-Interest Income	218,830	[2]	297,353	[2]
Banking Operations
Segment Reporting Information [Line Items]
Net interest income	1,144,820		1,128,591
Provisions for loan losses	30,758		62,988
Non-Interest Income	120,927		101,268
Non-interest expense	533,951	[1]	533,911	[1]
Income before income taxes	701,038		632,960
Income tax expense	254,738		222,325
Net income	446,300		410,635
Identifiable segment assets (period-end)	46,015,332		42,680,290
Banking Operations | Third Party
Segment Reporting Information [Line Items]
Non-Interest Income	137,534	[2]	116,063	[2]
Banking Operations | Inter-segment
Segment Reporting Information [Line Items]
Non-Interest Income	(16,607)		(14,795)
Residential Mortgage Banking
Segment Reporting Information [Line Items]
Net interest income	21,796		31,430
Non-Interest Income	97,903		196,085
Non-interest expense	73,611	[1]	79,566	[1]
Income before income taxes	46,088		147,949
Income tax expense	16,841		57,478
Net income	29,247		90,471
Identifiable segment assets (period-end)	672,955		1,464,810
Residential Mortgage Banking | Third Party
Segment Reporting Information [Line Items]
Non-Interest Income	81,296	[2]	181,290	[2]
Residential Mortgage Banking | Inter-segment
Segment Reporting Information [Line Items]
Non-Interest Income	$ 16,607		$ 14,795

[1] Includes both direct and indirect expenses.

[2] Includes ancillary fee income.