Condensed Consolidated Statements Of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 44,993	$ 42,231	$ 125,171	$ 110,994
Other comprehensive income, net of taxes: Securities:
Net change in unrealized gain during period	15,086	(9,875)	31,346	4,380
Reclassification adjustment for realized gain included in net income	(810)	0	(3,347)	(3,823)
Net change in non-credit related other-than-temporary impairment	0	0	0	746
Amortization of unrealized loss on securities transferred to held to maturity	14	27	92	77
Change in unrealized loss on derivative instruments	(708)	(19,700)	(220)	(22,416)
Defined benefit pension plans:
Amortization of net loss	1,007	406	3,021	1,217
Amortization of prior service cost	12	12	35	36
Current year actuarial gain	0	0	0	365
Other comprehensive income (loss)	14,601	(29,130)	30,927	(19,418)
Comprehensive income	59,594	13,101	156,098	91,576
Less: comprehensive loss attributable to non controlling interests	0	0	0	(1)
Comprehensive income attributable to Webster Financial Corporation	$ 59,594	$ 13,101	$ 156,098	$ 91,577