Supplemental Disclosures Related to Consolidated Statements of Cash Flows (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Supplemental cash flow information
Total interest costs incurred	$ 15,093	$ 13,901
Interest capitalized	357
Interest expense	14,736	13,901
Cash paid for interest, net of amounts capitalized (including discontinued operations)	13,128	13,379
Cash paid for income taxes		720
Supplemental schedule of noncash investing and financing activities
Accounts payable and accrued liabilities for construction in progress	556	(232)
Acquisition of working capital deficit, net of cash		$ (190)