Equity Compensation - Stock Options Granted, Forfeited, Exercised and Expired (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Number of shares
Number of Shares, Outstanding at beginning of period			1,574,604
Number of Shares, Granted	0	0	154,000	156,500
Number of Shares, Forfeited			(16,668)
Number of Shares, Exercised	0	4,855	0	202,820
Number of Shares, Expired			(361,988)
Number of Shares, Outstanding at end of period	1,349,948		1,349,948
Number of Shares, Exercisable at end of period	1,060,443		1,060,443
Weighted Average Exercise Price
Weighted Average Exercise Price, Outstanding at beginning of period			$ 84.90
Weighted Average Exercise Price, Granted			$ 19.31
Weighted Average Exercise Price, Forfeited			$ 75.11
Weighted Average Exercise Price, Exercised			$ 0.00
Weighted Average Exercise Price, Expired			$ 70.59
Weighted Average Exercise Price, Outstanding at end of period	$ 81.38		$ 81.38
Weighted Average Exercise Price, Exercisable at end of period	$ 91.47		$ 91.47
Aggregate Exercise Price
Aggregate Exercise Price, Outstanding at beginning of period			$ 133,691
Aggregate Exercise Price, Granted			2,974
Aggregate Exercise Price, Forfeited			(1,252)
Aggregate Exercise Price, Exercised			0
Aggregate Exercise Price, Expired			(25,554)
Aggregate Exercise Price, Outstanding at end of period	109,858		109,858
Aggregate Exercise Price, Exercisable at end of period	97,003		97,003
Weighted Average Remaining Contractual Term
Weighted Average Remaining Contractual Term, Outstanding at end of period, years			2 years 8 months 12 days
Weighted Average Remaining Contractual Term, Exercisable at end of period, years			2 years 3 months 18 days
Aggregate Intrinsic Value
Aggregate Intrinsic Value, Outstanding at end of period	1,800		1,800
Aggregate Intrinsic Value, Exercisable at end of period	$ 0		$ 0