Acquisitions (Narrative) (Detail) (USD $)	1 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended		3 Months Ended	9 Months Ended
	Feb. 17, 2012	Sep. 30, 2012	Sep. 30, 2011 Abington [Member]	Sep. 30, 2012 Abington [Member]	Sep. 30, 2011 Abington [Member]	Sep. 30, 2011 Tower [Member]	Sep. 30, 2012 Tower [Member]	Sep. 30, 2011 Tower [Member]	Sep. 30, 2012 Tower [Member] Real Estate Secured - Commercial [Member]	Sep. 30, 2012 Tower [Member] Commercial Loan And Leases [Member]	Sep. 30, 2012 Tower [Member] Residential Real Estate Loans [Member]
Business Acquisition [Line Items]
Number of offices operated by acquiree				20
Number of shares of Susquehanna common stock for each share of common stock				1.3200			3.4696
Number of shares of Susquehanna common shares issued				26,700,000			30,800,000
Acquisition of common stock	Feb. 17, 2012						Feb. 17, 2012
Cash paid per share, acquisition							$ 28.00
Aggregate consideration paid in cash	$ 88,005,000						$ 88,000,000
Assets acquired, total	2,391,157,000	2,391,157,000
Loans and leases	1,975,488,000	1,975,488,000							854,993,000	136,979,000	758,803,000
Aggregate liabilities assumed	2,251,770,000	2,251,770,000
Deposits	2,074,372,000	2,074,372,000
Transaction added to shareholders equity from acquisition		302,112,000
Net goodwill resulting from acquisition	250,730,000	250,730,000
Additional goodwill recorded		3,869,000
Core deposit intangible, amount to be amortized		24,005,000
Core deposit intangible amortized estimated useful life, years		10 years
Total revenue, net of interest expense and net income			152,400,000		455,500,000	173,200,000	573,800,000	517,800,000
Net income			17,000,000		41,500,000
Net income from continuing operations						$ 21,200,000	$ 98,100,000	$ 45,700,000