An excess of the fair value of the modified award over the fair value of the award immediately before the modification.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (h)(2)(iii)

-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 g(2)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Stock-Based Compensation (Performance Vested Awards Return on Investment Targets) (Details) (2010 Equity Incentive Plan, Restricted Stock, USD $) In Thousands, unless otherwise specified	6 Months Ended					12 Months Ended	6 Months Ended
	Jun. 30, 2013 Performance Vested	Jun. 30, 2013 Return On Investment Target One Performance Vested	Jun. 30, 2013 Return On Investment Target Two Performance Vested	Jun. 30, 2013 Return On Investment Target Three Performance Vested	Jun. 30, 2013 Return On Investment Target Four Performance Vested	Dec. 31, 2012 Return On Investment Target Five Market and Performance Vesting Conditions	Jun. 30, 2013 Return On Investment Target Five Performance Vested	Jun. 30, 2013 Maximum Performance Vested	Jun. 30, 2013 Maximum Time Vested
Stock-Based Compensation [Line Items]
Return On Investment Target Percentage		175.00%	200.00%	250.00%	300.00%	400.00%	350.00%
Incremental compensation cost	$ 4,322
Vesting Percentage		20.00%	20.00%	20.00%	20.00%		20.00%
Award vesting period								5 years	5 years