Selected Quarterly Consolidated Financial Information (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Quarterly Financial Information Disclosure [Abstract]
Interest income	$ 175,711	$ 171,753	$ 170,093	$ 170,083	$ 172,546	$ 172,216	$ 174,633	$ 174,107	$ 687,640	$ 693,502	$ 699,723
Interest expense	21,827	21,766	23,032	24,287	26,274	27,326	30,255	30,739	90,912	114,594	135,955
Net interest income	153,884	149,987	147,061	145,796	146,272	144,890	144,378	143,368	596,728	578,908	563,768
Provision for loan and lease losses	9,000	8,500	8,500	7,500	7,500	5,000	5,000	4,000	33,500	21,500	22,500
Net gain on sale of investment securities	4	269	333	106	0	810	2,537	0	712	3,347	3,823
Other non-interest income	44,260	45,988	51,918	48,172	52,940	47,669	44,816	43,986
Non-interest expense	126,639	122,281	123,604	125,535	122,925	123,887	127,179	127,813	498,059	501,804	510,976
Income from continuing operations before income tax expense	62,509	65,463	67,208	61,039	68,787	64,482	59,552	55,541	256,219	248,362	207,334
Income tax expense	18,755	18,158	20,835	18,922	20,261	19,489	18,312	16,603	76,670	74,665	57,951
Net income attributable to Webster Financial Corporation	43,754	47,305	46,373	42,117	48,526	44,993	41,240	38,938	179,549	173,697	151,379
Preferred stock dividends	(2,639)	(2,639)	(2,639)	(2,886)	(615)	(615)	(615)	(615)	(10,803)	(2,460)	(3,286)
Net income available to common shareholders	$ 41,115	$ 44,666	$ 43,734	$ 39,231	$ 47,911	$ 44,378	$ 40,625	$ 38,323	$ 168,746	$ 171,237	$ 148,093
Basic:
Net income available to common shareholders per common share, Basic (in dollars per share)	$ 0.46	$ 0.50	$ 0.49	$ 0.46	$ 0.55	$ 0.51	$ 0.46	$ 0.44	$ 1.90	$ 1.96	$ 1.69
Diluted:
Net income available to common shareholders per common share, Diluted (in dollars per share)	$ 0.45	$ 0.49	$ 0.48	$ 0.44	$ 0.52	$ 0.48	$ 0.44	$ 0.42	$ 1.86	$ 1.86	$ 1.61