Quarterly Results - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2015
Interim Reporting [Line Items]
Non cash impairment charges		$ 10,844,000
Non operating and non cash gain		$ 27,132,000
Three Quarters Ended September 30, 2014 [Member]
Interim Reporting [Line Items]
Share-based compensation expense reversal	$ 1,009,000
Three Years Ended December 31, 2013 [Member]
Interim Reporting [Line Items]
Share-based compensation expense reversal	$ 1,191,000