Summarized Consolidated Quarterly Information - Summarized Consolidated and Condensed Quarterly Financial Information (Parenthetical) (Detail) (USD $)	3 Months Ended		12 Months Ended			3 Months Ended			12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Gold Peak [Member]	Jun. 30, 2012 Gold Peak [Member]	Mar. 31, 2012 Gold Peak [Member]	Dec. 31, 2013 Gold Peak [Member]	Dec. 31, 2012 Gold Peak [Member]	Dec. 31, 2011 Gold Peak [Member]
Condensed Unaudited Quarterly Financial Data [Line Items]
Net tax benefit	$ 14,751,000	$ 5,427,000	$ 13,670,069	$ 5,427,000	$ 4,075,000
Litigation charge, net of recoveries			(80,000)	11,547,000	4,460,000			14,216,000		11,547,000	4,460,000
Reversal of litigation charge							1,956,000
Litigation recovery						$ 712,500			$ 80,000	$ 712,500