Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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+ Details

Earnings (Loss) Per Common Share - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Potentially dilutive securities excluded from computation of earning per share	4,943,000	2,119,000	1,606,000
Convertible Debt Securities
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Potentially dilutive securities excluded from computation of earning per share	1,263
3 3/4% Senior Subordinated Convertible Notes Due 2012
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Convertible notes maturity date	Jul. 15, 2012
Senior subordinated convertible notes, interest percentage	3.75%