Business Segment Information (Intercompany Segment Assets) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Assets	$ 2,666,331	$ 3,386,580
Contracting Services [Member]
Assets	2,141,930	1,974,763
Production Facilities [Member]
Assets	496,986	503,531
Corporate and Other [Member]
Assets	27,415	8,059
Discontinued Operations [Member]
Assets		$ 900,227