Derivatives (Derivative Instruments Consolidated Statement) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended	12 Months Ended
Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012 Interest Rate Swap [Member]	Dec. 31, 2011 Interest Rate Swap [Member]	Dec. 31, 2010 Interest Rate Swap [Member]
Derivative [Line Items]
Included in Interest Income / (Expense)	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0
Included in Other Income / (Expense)	$ 549	$ 0	$ 551	$ 0	$ 163	$ 0	$ 0

Reflects the sum of all other revenue and income recognized by the entity in the period not otherwise specified in the income statement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-04.4)

-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 4

-Article 7

Name:	us-gaap_OtherIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration