Segment Information - Information about Company's Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]
Net income (loss)	$ 229,017	$ 274,113
Business Banking [Member]
Segment Reporting Information [Line Items]
Net income (loss)	28,598	32,561
Commercial Banking [Member]
Segment Reporting Information [Line Items]
Net income (loss)	99,765	107,387
Commercial Real Estate [Member]
Segment Reporting Information [Line Items]
Net income (loss)	74,561	76,508
Discretionary Portfolio [Member]
Segment Reporting Information [Line Items]
Net income (loss)	11,279	1,846
Residential Mortgage Banking [Member]
Segment Reporting Information [Line Items]
Net income (loss)	19,411	34,361
Retail Banking [Member]
Segment Reporting Information [Line Items]
Net income (loss)	29,711	52,350
All Other [Member]
Segment Reporting Information [Line Items]
Net income (loss)	(34,308)	(30,900)
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues	1,076,540	1,088,932
Operating Segments [Member] | Business Banking [Member]
Segment Reporting Information [Line Items]
Total revenues	102,299	105,418
Operating Segments [Member] | Commercial Banking [Member]
Segment Reporting Information [Line Items]
Total revenues	248,586	249,850
Operating Segments [Member] | Commercial Real Estate [Member]
Segment Reporting Information [Line Items]
Total revenues	158,360	165,293
Operating Segments [Member] | Discretionary Portfolio [Member]
Segment Reporting Information [Line Items]
Total revenues	24,657	12,041
Operating Segments [Member] | Residential Mortgage Banking [Member]
Segment Reporting Information [Line Items]
Total revenues	94,588	119,899
Operating Segments [Member] | Retail Banking [Member]
Segment Reporting Information [Line Items]
Total revenues	261,888	291,185
Operating Segments [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Total revenues	186,162	145,246
Intersegment activity eliminated in consolidated totals [Member]
Segment Reporting Information [Line Items]
Total revenues
Intersegment activity eliminated in consolidated totals [Member] | Business Banking [Member]
Segment Reporting Information [Line Items]
Total revenues	1,057	1,194
Intersegment activity eliminated in consolidated totals [Member] | Commercial Banking [Member]
Segment Reporting Information [Line Items]
Total revenues	1,197	1,350
Intersegment activity eliminated in consolidated totals [Member] | Commercial Real Estate [Member]
Segment Reporting Information [Line Items]
Total revenues	348	1,552
Intersegment activity eliminated in consolidated totals [Member] | Discretionary Portfolio [Member]
Segment Reporting Information [Line Items]
Total revenues	(5,039)	(8,601)
Intersegment activity eliminated in consolidated totals [Member] | Residential Mortgage Banking [Member]
Segment Reporting Information [Line Items]
Total revenues	9,748	18,698
Intersegment activity eliminated in consolidated totals [Member] | Retail Banking [Member]
Segment Reporting Information [Line Items]
Total revenues	3,505	3,257
Intersegment activity eliminated in consolidated totals [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Total revenues	$ (10,816)	$ (17,450)