Accumulated Other Comprehensive Loss (Components Of AOCI) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Loss, Beginning Balance			$ (37,258)
Sale of securities for which other-than-temporary impairment was previously recognized, net of tax	0	3,180	0	3,180
Interest Expense	26,314	31,189	52,508	63,003
Net realized loss (gain) on sales of securities	(71)	1,361	(53)	1,602
Accumulated Other Comprehensive Loss, Ending Balance	(65,922)		(65,922)
Unrealized Gains (Losses) On Investment Securities With OTTI [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Loss, Beginning Balance	(1,024)	(4,423)	(839)	(2,564)
AOCI Before Reclassifications, Net Of Tax	211	70	(226)	(1,912)
Sale of securities for which other-than-temporary impairment was previously recognized, net of tax		2,892		2,892
Net Change In AOCI	274	2,962	89	1,103
Accumulated Other Comprehensive Loss, Ending Balance	(750)	(1,461)	(750)	(1,461)
Unrealized Gains (Losses) On Investment Securities With OTTI [Member] | Amounts Reclassified From AOCI
Accumulated Other Comprehensive Income Loss [Line Items]
Interest Expense	0	0	0	0
Net realized loss (gain) on sales of securities	97	0	485	190
Total Before Income Taxes	97	0	485	190
Less: Income Taxes	(34)	0	(170)	(67)
Net Of Income Taxes	63	0	315	123
Unrealized Gains (Losses) On Investment Securities All Other [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Loss, Beginning Balance	33,529	24,311	37,521	23,389
AOCI Before Reclassifications, Net Of Tax	(33,926)	4,243	(37,654)	5,438
Sale of securities for which other-than-temporary impairment was previously recognized, net of tax		0		0
Net Change In AOCI	(33,943)	3,381	(37,935)	4,303
Accumulated Other Comprehensive Loss, Ending Balance	(414)	27,692	(414)	27,692
Unrealized Gains (Losses) On Investment Securities All Other [Member] | Amounts Reclassified From AOCI
Accumulated Other Comprehensive Income Loss [Line Items]
Interest Expense	0	0	0	0
Net realized loss (gain) on sales of securities	(26)	(1,361)	(432)	(1,792)
Total Before Income Taxes	(26)	(1,361)	(432)	(1,792)
Less: Income Taxes	9	499	151	657
Net Of Income Taxes	(17)	(862)	(281)	(1,135)
Unrealized Gains (Losses) On Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Loss, Beginning Balance	(31,839)	(31,704)	(34,636)	(33,402)
AOCI Before Reclassifications, Net Of Tax	3,368	(7,019)	3,218	(8,102)
Sale of securities for which other-than-temporary impairment was previously recognized, net of tax		0		0
Net Change In AOCI	6,402	(4,178)	9,199	(2,480)
Accumulated Other Comprehensive Loss, Ending Balance	(25,437)	(35,882)	(25,437)	(35,882)
Unrealized Gains (Losses) On Cash Flow Hedges [Member] | Amounts Reclassified From AOCI
Accumulated Other Comprehensive Income Loss [Line Items]
Interest Expense	4,668	4,369	9,202	8,649
Net realized loss (gain) on sales of securities	0	0	0	0
Total Before Income Taxes	4,668	4,369	9,202	8,649
Less: Income Taxes	(1,634)	(1,528)	(3,221)	(3,027)
Net Of Income Taxes	3,034	2,841	5,981	5,622
Post-Retirement Benefits [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Loss, Beginning Balance	(39,321)	(33,477)	(39,304)	(33,477)
AOCI Before Reclassifications, Net Of Tax	0	0	(17)	0
Sale of securities for which other-than-temporary impairment was previously recognized, net of tax		0		0
Net Change In AOCI	0	0	(17)	0
Accumulated Other Comprehensive Loss, Ending Balance	(39,321)	(33,477)	(39,321)	(33,477)
Post-Retirement Benefits [Member] | Amounts Reclassified From AOCI
Accumulated Other Comprehensive Income Loss [Line Items]
Interest Expense	0	0	0	0
Net realized loss (gain) on sales of securities	0	0	0	0
Total Before Income Taxes	0	0	0	0
Less: Income Taxes	0	0	0	0
Net Of Income Taxes	0	0	0	0
Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Loss, Beginning Balance	(38,655)	(45,293)	(37,258)	(46,054)
AOCI Before Reclassifications, Net Of Tax	(30,347)	(2,706)	(34,679)	(4,576)
Sale of securities for which other-than-temporary impairment was previously recognized, net of tax		2,892		2,892
Net Change In AOCI	(27,267)	2,165	(28,664)	2,926
Accumulated Other Comprehensive Loss, Ending Balance	(65,922)	(43,128)	(65,922)	(43,128)
Accumulated Other Comprehensive Loss [Member] | Amounts Reclassified From AOCI
Accumulated Other Comprehensive Income Loss [Line Items]
Interest Expense	4,668	4,369	9,202	8,649
Net realized loss (gain) on sales of securities	71	(1,361)	53	(1,602)
Total Before Income Taxes	4,739	3,008	9,255	7,047
Less: Income Taxes	(1,659)	(1,029)	(3,240)	(2,437)
Net Of Income Taxes	$ 3,080	$ 1,979	$ 6,015	$ 4,610