Amount of contributions made to multiemployer plans for each period for which a statement of income is presented. An employer may disclose total contributions to multiemployer plans without disaggregating the amounts attributable to pension plans and other postretirement benefit plans.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 12

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Section 50

-Paragraph 1

-SubTopic 80

-Topic 715

-URI http://asc.fasb.org/extlink&oid=6958064&loc=d3e29142-114947

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

Subsequent Events (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended		1 Months Ended		3 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Jan. 31, 2012 Multi-employer defined benefit pension plan	Jan. 31, 2011 Multi-employer defined benefit pension plan	Mar. 31, 2012 Multi-employer defined benefit pension plan Minimum	Mar. 31, 2012 Multi-employer defined benefit pension plan Maximum
Subsequent Events
Percentage of funded status			65.80%	83.60%
Percentage of funded status of current market value of investment				70.00%
Percentage of plan surcharge					5.00%	10.00%
Contributions	$ 2,046	$ 1,923