Pension and Other Postretirement Benefits (Changes in Plan Assets and Funded Status of Pension Plans and Other Postretirement Benefit Plans) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Change in plan assets:
Fair value of plan assets at end of year	$ 172,976	$ 162,182
Webster Pension [Member]
Change in benefit obligation:
Benefit obligation at beginning of year	171,189	187,145
Service cost	40	40	30
Interest cost	8,068	7,365	7,307
Actuarial loss (gain)	38,472	(17,909)
Benefit payments, administrative expenses, and interest income, net	(7,221)	(5,452)
Benefit obligation at end of year	210,548	171,189	187,145
Change in plan assets:
Fair value of plan assets at beginning of year	162,182	151,191
Actual return on plan assets	18,015	16,443
Employer contributions	0	0
Benefit payments, administrative expenses, and interest income, net	(7,221)	(5,452)
Fair value of plan assets at end of year	172,976	162,182	151,191
Funded status of the plan at year end accrued liability recognized	(37,572)	(9,007)
Webster SERP [Member]
Change in benefit obligation:
Benefit obligation at beginning of year	8,675	8,660
Service cost	0	0	0
Interest cost	364	289	316
Actuarial loss (gain)	1,145	(160)
Benefit payments, administrative expenses, and interest income, net	(143)	(114)
Benefit obligation at end of year	10,041	8,675	8,660
Change in plan assets:
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	143	114
Benefit payments, administrative expenses, and interest income, net	(143)	(114)
Fair value of plan assets at end of year	0	0	0
Funded status of the plan at year end accrued liability recognized	(10,041)	(8,675)
Other Benefits [Member]
Change in benefit obligation:
Benefit obligation at beginning of year	3,821	4,229
Service cost	0	0	0
Interest cost	139	109	177
Actuarial loss (gain)	470	(239)
Benefit payments, administrative expenses, and interest income, net	(297)	(278)
Benefit obligation at end of year	4,133	3,821	4,229
Change in plan assets:
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	297	278
Benefit payments, administrative expenses, and interest income, net	(297)	(278)
Fair value of plan assets at end of year	0	0	0
Funded status of the plan at year end accrued liability recognized	$ (4,133)	$ (3,821)