Consolidated Statements Of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Statement of Other Comprehensive Income [Abstract]
Net income	$ 173,697	$ 151,378	$ 72,258
Other comprehensive income, net of taxes:
Net unrealized gain during the period	28,928	4	28,677
Net non-credit related other-than-temporary impairment	0	746	(6,342)
Reclassification adjustment for net gain included in net income	(2,176)	(2,485)	(2,542)
Amortization of unrealized loss on securities transferred to held to maturity	22	173	331
Change in unrealized gain (loss) on derivative instruments	982	(22,995)	(2,768)
Defined benefit pension and other post retirement benefit plans:
Amortization of net loss	4,032	1,733	1,477
Amortization of prior service cost	47	46	47
Current year actuarial gain	(3,897)	(23,717)	(4,200)
Other comprehensive income (loss)	27,938	(46,495)	14,680
Comprehensive income	201,635	104,883	86,938
Less: comprehensive (loss) income attributable to non controlling interests	0	(1)	3
Comprehensive income attributable to Webster Financial Corporation	$ 201,635	$ 104,884	$ 86,935