Accumulated Other Comprehensive Loss (Components Of AOCI) (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Loss, Beginning Balance			$ (51,566,000)
Interest Expense	25,270,000	25,128,000	70,685,000	77,636,000
Net Realized Loss (Gain) On Sales And Impairment Of Securities	0	2,000	3,285,000	(51,000)
Accumulated Other Comprehensive Loss, Ending Balance	(26,131,000)		(26,131,000)
Unrealized Gains (Losses) On Investment Securities With OTTI [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Loss, Beginning Balance	(279,000)	(750,000)	(279,000)	(839,000)
AOCI Before Reclassifications, Net Of Tax	0	150,000	0	(76,000)
Net Change In AOCI	0	150,000	0	239,000
Accumulated Other Comprehensive Loss, Ending Balance	(279,000)	(600,000)	(279,000)	(600,000)
Unrealized Gains (Losses) On Investment Securities With OTTI [Member] | Amounts Reclassified From AOCI [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Interest Expense	0	0	0	0
Net Realized Loss (Gain) On Sales And Impairment Of Securities	0	0	0	485,000
Total Before Income Taxes	0	0	0	485,000
Less: Income Taxes	0	0	0	(170,000)
Net Of Income Taxes	0	0	0	315,000
Unrealized Gains (Losses) On Investment Securities All Other [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Loss, Beginning Balance	10,320,000	(414,000)	(7,195,000)	37,521,000
AOCI Before Reclassifications, Net Of Tax	(908,000)	1,994,000	18,742,000	(35,660,000)
Net Change In AOCI	(908,000)	1,993,000	16,607,000	(35,942,000)
Accumulated Other Comprehensive Loss, Ending Balance	9,412,000	1,579,000	9,412,000	1,579,000
Unrealized Gains (Losses) On Investment Securities All Other [Member] | Amounts Reclassified From AOCI [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Interest Expense	0	0	0	0
Net Realized Loss (Gain) On Sales And Impairment Of Securities	0	(2,000)	(3,285,000)	(434,000)
Total Before Income Taxes	0	(2,000)	(3,285,000)	(434,000)
Less: Income Taxes	0	1,000	1,150,000	152,000
Net Of Income Taxes	0	(1,000)	(2,135,000)	(282,000)
Unrealized Gains (Losses) On Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Loss, Beginning Balance	(16,874,000)	(25,437,000)	(21,683,000)	(34,636,000)
AOCI Before Reclassifications, Net Of Tax	396,000	(2,434,000)	(1,869,000)	784,000
Net Change In AOCI	4,019,000	831,000	8,828,000	10,030,000
Accumulated Other Comprehensive Loss, Ending Balance	(12,855,000)	(24,606,000)	(12,855,000)	(24,606,000)
Unrealized Gains (Losses) On Cash Flow Hedges [Member] | Amounts Reclassified From AOCI [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Interest Expense	5,574,000	5,023,000	16,457,000	14,225,000
Net Realized Loss (Gain) On Sales And Impairment Of Securities	0	0	0	0
Total Before Income Taxes	5,574,000	5,023,000	16,457,000	14,225,000
Less: Income Taxes	(1,951,000)	(1,758,000)	(5,760,000)	(4,979,000)
Net Of Income Taxes	3,623,000	3,265,000	10,697,000	9,246,000
Post-Retirement Benefits [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Loss, Beginning Balance	(22,409,000)	(39,321,000)	(22,409,000)	(39,304,000)
AOCI Before Reclassifications, Net Of Tax	0	0	0	(17,000)
Net Change In AOCI	0	0	0	(17,000)
Accumulated Other Comprehensive Loss, Ending Balance	(22,409,000)	(39,321,000)	(22,409,000)	(39,321,000)
Post-Retirement Benefits [Member] | Amounts Reclassified From AOCI [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Interest Expense	0	0	0	0
Net Realized Loss (Gain) On Sales And Impairment 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	(29,242,000)	(65,922,000)	(51,566,000)	(37,258,000)
AOCI Before Reclassifications, Net Of Tax	(512,000)	(290,000)	16,873,000	(34,969,000)
Net Change In AOCI	3,111,000	2,974,000	25,435,000	(25,690,000)
Accumulated Other Comprehensive Loss, Ending Balance	(26,131,000)	(62,948,000)	(26,131,000)	(62,948,000)
Accumulated Other Comprehensive Loss [Member] | Amounts Reclassified From AOCI [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Interest Expense	5,574,000	5,023,000	16,457,000	14,225,000
Net Realized Loss (Gain) On Sales And Impairment Of Securities	0	(2,000)	(3,285,000)	51,000
Total Before Income Taxes	5,574,000	5,021,000	13,172,000	14,276,000
Less: Income Taxes	(1,951,000)	(1,757,000)	(4,610,000)	(4,997,000)
Net Of Income Taxes	$ 3,623,000	$ 3,264,000	$ 8,562,000	$ 9,279,000