Securities (Narrative) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Schedule of Securities [Line Items]
Securities pledged to secure public deposits, trust deposits, and for other purposes, carrying value	$ 547,727	$ 651,299	$ 598,078
Securities pledged as collateral for short-term borrowings, carrying value	680,212	676,083	616,000
Gross gains relating to sale of securities	3,415	2,291
Total securities sold	101,973	60,165	812
Held to maturity securities, book value	917,212	940,481	775,281
Percentage of current collateral securities	77.42%
Recognized impairment losses on securities	66	2,339	7,893
Deferral Rates after the deferral period ends minimum	10.00%
Deferral Rates after the deferral period ends maximum	90.00%
Recover rate of banks	10.00%
Recover rate of insurance companies	15.00%
Number of single issue securities	5
Estimated fair value of single-issue trust preferred securities	6,341
Estimated fair value of pooled trust preferred securities	7,276
Number of non-performing investments	12
Adoption of Revised ASC 320 as previously recorded OTTI charges	7,021
Adoption of Revised ASC 320	4,563		4,563
Adoption of Revised ASC 320, taxes	2,458
Impairment losses related to stocks	0	58	735
Non-credit related losses on securities not expected to be sold (recognized in other comprehensive income)	829	7,251	17,339
Non-credit related losses on securities not expected to be sold recognized in other comprehensive income, net of tax	539	4,713	11,270
Credit related losses on securities not expected to be sold recognized in other comprehensive income	66	2,281	7,158
Number of stock held by the corporation	12
Adjusted cost basis of bank stock	1,567
Fair value of bank stock	1,790
Purchase of non-agency collateralized mortgage obligations from 2003 through 2005	161,151
Municipal bond portfolio, value	188,098
Percent of municipal bond portfolio rated A or better	99.80%
Percent of municipal bond portfolio consisting of general obligation bonds	100.00%
Percent of municipal bonds from Pennsylvania	76.90%
Average holding size of municipal bonds	1,011
Percent of portfolio with credit support	80.40%
Non-agency collateralized mortgage obligations paydown balance on maturity	9,184
Annualized payout rate	27.10%
Ratio of original average loan-to-value	66.10%
Original credit score	724
Credit related loss recognized	29
Residential Mortgage-Backed Securities [Member]
Schedule of Securities [Line Items]
Total securities sold	83,736	52,625
Securities continuous unrealized loss position less than twelve months, number of investments	4
Securities continuous unrealized loss position greater than twelve months, number of investments	1
Agency Collateralized Mortgage Obligations [Member]
Schedule of Securities [Line Items]
Securities continuous unrealized loss position less than twelve months, number of investments	1
Held to maturity securities, book value	54,319
Non-Agency Collateralized Mortgage Obligations [Member]
Schedule of Securities [Line Items]
Securities continuous unrealized loss position less than twelve months, number of investments	3
Held to maturity securities, book value	24,348
Collateralized Debt Obligations [Member]
Schedule of Securities [Line Items]
Securities continuous unrealized loss position greater than twelve months, number of investments	13
Other Debt Securities [Member]
Schedule of Securities [Line Items]
Securities continuous unrealized loss position greater than twelve months, number of investments	5
Equity Securities [Member]
Schedule of Securities [Line Items]
Securities continuous unrealized loss position less than twelve months, number of investments	2
Securities continuous unrealized loss position greater than twelve months, number of investments	2
Mezzanine Tranches [Member]
Schedule of Securities [Line Items]
Number of pooled issue securities	12
U.S. Government Agencies Debt Securities [Member]
Schedule of Securities [Line Items]
Total securities sold	3,940	6,016
Total Pooled TPS [Member]
Schedule of Securities [Line Items]
Number of pooled issue securities	13
Recognized impairment losses on securities	$ 895	$ 9,532	$ 24,497
Maximum [Member]
Schedule of Securities [Line Items]
Deferral rate after five years	90.00%
Range of credit loss	7.00%
Range of grown percentage of credit support due to paydowns and good credit performance	20.20%
Minimum [Member]
Schedule of Securities [Line Items]
Deferral rate after five years	10.00%
Range of credit loss	2.00%
Range of grown percentage of credit support due to paydowns and good credit performance	1.80%