Equity Compensation - Stock Options Granted, Forfeited, Exercised and Expired (Detail) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
		Mar. 31, 2014	Mar. 31, 2013
Number of shares
Number of Shares, Outstanding at beginning of period		1,332,448
Number of Shares, Granted		168,500	0
Number of Shares, Forfeited		(10,334)
Number of Shares, Exercised		0	0
Number of Shares, Expired		(180,239)
Number of Shares, Outstanding at end of period		1,310,375
Number of Shares, Exercisable at end of period		954,536
Weighted Average Exercise Price
Weighted Average Exercise Price, Outstanding at beginning of period		$ 81.77
Weighted Average Exercise Price, Granted		27.94
Weighted Average Exercise Price, Forfeited		30.29
Weighted Average Exercise Price, Exercised		0
Weighted Average Exercise Price, Expired		66.13
Weighted Average Exercise Price, Outstanding at end of period		77.40
Weighted Average Exercise Price, Exercisable at end of period		$ 95.21
Aggregate Exercise Price
Aggregate Exercise Price, Outstanding at beginning of period		$ 108,955
Aggregate Exercise Price, Granted		4,708
Aggregate Exercise Price, Forfeited		(313)
Aggregate Exercise Price, Exercised		0
Aggregate Exercise Price, Expired		(11,919)
Aggregate Exercise Price, Outstanding at end of period		101,431
Aggregate Exercise Price, Exercisable at end of period		$ 90,882
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]	$ 1,522
Aggregate Intrinsic Value, Exercisable at end of period	[1]	$ 0

[1] The aggregate intrinsic value of the stock options was calculated by identifying those stock options that had a lower exercise price than the closing market price of our common stock on March 31, 2014 and multiplying the difference between the closing market price of our common stock and the exercise price of each of those stock options by the number of shares subject to those stock options that were outstanding or exercisable, as applicable.