Quarterly Financial Data - Schedule of Quarterly Financial Information (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Schedule Of Quarterly Financial Data [Line Items]
Gross profit	$ 40,370	$ 33,187	$ 65,735	$ 44,444	$ 62,821	$ 34,257	$ 72,086	$ 53,854	$ 183,736	$ 223,018	$ 138,625
Income from continuing operations	11,622	6,710	26,130	14,324	28,002	6,324	28,698	20,960	58,786	83,984	29,715
Business interruption insurance recovery [Member]
Schedule Of Quarterly Financial Data [Line Items]
Gross profit	7,300						8,605
Income from continuing operations	$ 7,300						$ 8,605