Derivative and Hedging Activities (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2011	Dec. 31, 2010
Summary of Fair Value of Derivative Instruments Designated as Cash flow hedges
Notional Amount	$ 200,000	$ 200,000
Interest rate swaps [Member] \| Other liabilities [Member]
Summary of Fair Value of Derivative Instruments Designated as Cash flow hedges
Notional Amount	200,000	200,000
Fair Value	$ (3,634)	$ (6,295)
Interest rate swaps [Member] \| Other liabilities [Member] \| Cash flow hedges [Member]
Summary of Fair Value of Derivative Instruments Designated as Cash flow hedges
Maturity	8 months	14 months
Receive Rate	0.09%	0.19%
Pay Rate	3.15%	3.15%

Aggregate notional amount of all interest rate derivatives designated as hedging instruments in cash flow hedges. Notional amount refers to the monetary amount specified in the interest rate derivative contract.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Notional Amount
-URI http://asc.fasb.org/extlink&oid=6519104

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5579245-113959

Name:	us-gaap_NotionalAmountOfInterestRateCashFlowHedgeDerivatives
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant