Equity Compensation Plans - Stock Options Granted, Forfeited, Exercised and Expired (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Number of shares
Number of Shares, Outstanding at beginning of period	1,574,604
Number of Shares, Granted	156,500	156,500	159,500
Number of Shares, Forfeited	(16,668)
Number of Shares, Exercised	0	202,820	118,410
Number of Shares, Expired	(381,988)
Number of Shares, Outstanding at end of period	1,332,448	1,574,604
Number of Shares, Exercisable at end of period	1,040,443
Weighted Average Exercise Price
Weighted Average Exercise Price, Outstanding at beginning of period	$ 84.90
Weighted Average Exercise Price, Granted	$ 19.55
Weighted Average Exercise Price, Forfeited	$ 75.11
Weighted Average Exercise Price, Exercised	$ 0.00
Weighted Average Exercise Price, Expired	$ 69.48
Weighted Average Exercise Price, Outstanding at end of period	$ 81.77	$ 84.90
Weighted Average Exercise Price, Exercisable at end of period	$ 92.28
Aggregate Exercise Price
Aggregate Exercise Price, Outstanding at beginning of period	$ 133,691
Aggregate Exercise Price, Granted	3,059
Aggregate Exercise Price, Forfeited	(1,252)
Aggregate Exercise Price, Exercised	0
Aggregate Exercise Price, Expired	(26,543)
Aggregate Exercise Price, Outstanding at end of period	108,955	133,691
Aggregate Exercise Price, Exercisable at end of period	96,016
Weighted Average Remaining Contractual Term
Weighted Average Remaining Contractual Term, Outstanding at end of period, years	2 years 4 months 24 days
Weighted Average Remaining Contractual Term, Exercisable at end of period, years	2 years 1 month 6 days
Aggregate Intrinsic Value
Aggregate Intrinsic Value, Outstanding at end of period	2,198
Aggregate Intrinsic Value, Exercisable at end of period	$ 0