Certain Employee Benefit and Stock Based Compensation Plans (Nonvested Cash-Payable Restricted Share Unit - Rollforward) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
Jun. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate Intrinsic Value of non-vested, cash-payable restricted unit shares	$ 68,944
Nonvested Cash Payable Restricted Share Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested Incentive/Performance Unit Share Awards and Restricted Stock/Share Unit Awards, Beginning balance	920
Granted	485
Vested/Released	(457)
Forfeited	(2)
Nonvested Incentive/Performance Unit Share Awards and Restricted Stock/hare Unit Awards, Ending balance	946

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(i)-(ii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(2)(b)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(2)(a)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant