Consolidated Statements of Changes in Shareholders' Equity (USD $)	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]
Balance at Dec. 31, 2011	$ 2,189,628,000	$ 314,136,000	$ (1,263,000)	$ 1,397,152,000	$ 525,657,000	$ (46,054,000)
Balance, Shares at Dec. 31, 2011	157,067,887
Total comprehensive income	112,687,000				97,998,000	14,689,000
Issuance of common stock in Tower Bancorp, Inc. acquisition	302,112,000	61,522,000		240,590,000
Issuance of common stock in Tower Bancorp, Inc. acquisition (Shares)		30,760,933
Retirement of common stock related to acquired employee benefit plans	0	(3,723,000)		3,723,000
Retirement of common stock related to acquired employee benefit plans (Shares)		1,861,580
Issuance of common stock and share-based awards under employee benefit plans (shares)		709,012
Issuance of common stock and share-based awards under employee benefit plans	5,644,000	1,417,000		4,227,000
Treasury stock purchased	(105,000)		(105,000)
Cash dividends paid on common stock	(25,284,000)				(25,284,000)
Balance at Sep. 30, 2012	2,584,682,000	373,352,000	(1,368,000)	1,645,692,000	598,371,000	(31,365,000)
Balance, shares at Sep. 30, 2012	186,676,252
Balance at Dec. 31, 2012	2,595,909,000	373,623,000	(1,850,000)	1,645,958,000	615,436,000	(37,258,000)
Balance, Shares at Dec. 31, 2012	186,811,642
Total comprehensive income	106,648,000				132,338,000	(25,690,000)
Issuance of common stock and share-based awards under employee benefit plans (shares)		679,487
Issuance of common stock and share-based awards under employee benefit plans	6,783,000	1,359,000		5,424,000
Treasury stock purchased	(68,000)		(68,000)
Cash dividends paid on common stock	(29,924,000)				(29,924,000)
Balance at Sep. 30, 2013	$ 2,679,348,000	$ 374,982,000	$ (1,918,000)	$ 1,651,382,000	$ 717,850,000	$ (62,948,000)
Balance, shares at Sep. 30, 2013	187,491,129