Derivatives, Hedges, Financial Instruments and Carbon Credits - Additional Information (Detail)	3 Months Ended	12 Months Ended
	Mar. 31, 2017 USD ($) Unit $ / shares $ / Transaction shares	Dec. 31, 2016 USD ($) Unit $ / shares $ / Transaction shares
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Number of carbon credits | Unit	369,000	0
Series E redeemable preferred - embedded derivative	$ 2,848,000	$ 2,557,000
Carbon credit fair value per unit | $ / Transaction	2.35	0
Assets measured at fair value on a recurring basis transferred between Level 1 and Level 2 classifications	$ 0
Assets measured at fair value on a recurring basis transferred between Level 2 and Level 1 classifications	0
Liabilities measured at fair value on a recurring basis transferred between Level 1 and Level 2 classifications	0
Liabilities measured at fair value on a recurring basis transferred between Level 2 and Level 1 classifications	0
Embedded Derivative [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Series E redeemable preferred - embedded derivative	$ 0
Participating right in dividends and liquidating distributions expressed in number of common shares | shares	303,646	303,646
Embedded Derivative [Member] | Common Stock Shares [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Common stock per share | $ / shares	$ 9.38	$ 8.42