Aggregate notional amount of all interest rate derivatives designated as hedging instruments in fair value 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 1A

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5579245-113959

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 1B

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5580258-113959

Name:	us-gaap_NotionalAmountOfInterestRateFairValueHedgeDerivatives
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Derivatives (Details Textual) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Derivative [Line Items]
Notional value of interest rate swap and cap agreements	$ 233,669		$ 233,669
Derivatives (Textual) [Abstract]
Ineffective expense of cash flow derivatives			0	71
Swap [Member]
Derivative [Line Items]
Change in fair value of swaps	401	(1,022)	549	(170)
Interest Rate Swap [Member]
Derivative [Line Items]
Notional value of interest rate swap and cap agreements	$ 233,669		$ 233,669