Renewable Energy (REGI) 10-K 9 Mar 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Feb. 28, 2018	Jun. 30, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	Renewable Energy Group, Inc.
Entity Central Index Key	1,463,258
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Amendment Flag	false
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Public Float			$ 490,235,252
Entity Common Stock, Shares Outstanding		38,855,313

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
CURRENT ASSETS:
Cash and cash equivalents	$ 77,627	$ 116,210
Accounts receivable, net	90,648	164,949
Inventories	135,547	145,408
Prepaid expenses and other assets	51,880	36,272
Total current assets	355,702	462,839
Property, plant and equipment, net	587,397	599,474
Goodwill	16,080	16,080
Intangible assets, net	27,127	29,470
Investments	12,250	12,110
Other assets	7,040	12,630
Restricted cash	0	4,000
TOTAL ASSETS	1,005,596	1,136,603
CURRENT LIABILITIES:
Revolving lines of credit	65,525	52,844
Current maturities of long-term debt	13,397	15,402
Accounts payable	84,608	99,137
Accrued expenses and other liabilities	39,187	38,916
Deferred revenue	2,218	27,246
Total current liabilities	204,935	233,545
Unfavorable lease obligation	3,388	15,515
Deferred income taxes	8,192	20,279
Long-term contingent consideration for acquisitions	8,849	28,931
Convertible debt conversion liability	0	27,100
Long-term debt (net of debt issuance costs of $6,627 and $6,286, respectively)	208,536	196,203
Other liabilities	4,114	4,856
Total liabilities	438,014	526,429
COMMITMENTS AND CONTINGENCIES
EQUITY:
Common stock ($.0001 par value; 300,000,000 shares authorized; 38,837,749 and 38,553,413 shares outstanding, respectively)	5	5
Common stock—additional paid-in-capital	515,452	480,906
Retained earnings	134,928	214,007
Accumulated other comprehensive income (loss)	278	(5,751)
Treasury stock (9,363,166 and 9,246,002 shares, respectively)	(83,081)	(81,824)
Total equity attributable to the Company's shareholders	567,582	607,343
Noncontrolling interest	0	2,831
Total equity	567,582	610,174
TOTAL LIABILITIES AND EQUITY	$ 1,005,596	$ 1,136,603

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Debt issuance costs	$ 6,627	$ 6,286
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares, outstanding (in shares)	38,837,749	38,553,413
Treasury stock, shares outstanding (in shares)	9,363,166	9,246,002

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
REVENUES:
Biomass-based diesel sales	$ 1,787,308,000	$ 1,417,595,000	$ 954,742,000
Separated RIN sales	337,501,000	274,800,000	186,539,000
Biomass-based diesel government incentives	28,728,000	346,672,000	245,868,000
Total biomass-based diesel revenues	2,153,537,000	2,039,067,000	1,387,149,000
Other revenues	4,706,000	2,165,000	195,000
Total revenues	2,158,243,000	2,041,232,000	1,387,344,000
COSTS OF GOODS SOLD:
Biomass-based diesel	1,805,410,000	1,616,991,000	1,093,979,000
Separated RINs	264,765,000	250,809,000	182,688,000
Other costs of goods sold	4,487,000	1,916,000	134,000
Total cost of goods sold	2,074,662,000	1,869,716,000	1,276,801,000
GROSS PROFIT	83,581,000	171,516,000	110,543,000
SELLING, GENERAL, AND ADMINISTRATIVE EXPENSES	93,425,000	88,285,000	73,397,000
RESEARCH AND DEVELOPMENT EXPENSE	14,091,000	18,163,000	16,851,000
IMPAIRMENT OF PROPERTY, PLANT, AND EQUIPMENT	49,873,000	17,893,000	0
IMPAIRMENT OF GOODWILL	0	0	175,028,000
INCOME (LOSS) FROM OPERATIONS	(73,808,000)	47,175,000	(154,733,000)
OTHER INCOME (EXPENSE), NET:
Change in fair value of contingent consideration	(2,484,000)	(7,904,000)	359,000
Change in fair value of convertible debt conversion liability	(18,833,000)	13,045,000	0
Gain on debt extinguishment	0	2,331,000	0
Gain on involuntary conversion	5,329,000	9,894,000	0
Other income (expense)	(1,018,000)	427,000	5,830,000
Interest expense	(18,755,000)	(15,987,000)	(11,867,000)
Total other income (expense), net	(35,761,000)	1,806,000	(5,678,000)
INCOME (LOSS) BEFORE INCOME TAXES	(109,569,000)	48,981,000	(160,411,000)
INCOME TAX BENEFIT (EXPENSE)	30,490,000	(4,268,000)	8,701,000
NET INCOME (LOSS)	(79,079,000)	44,713,000	(151,710,000)
LESS—NET INCOME (LOSS) ATTRIBUTABLE TO NONCONTROLLING INTEREST	0	386,000	(318,000)
NET INCOME (LOSS) ATTRIBUTABLE TO THE COMPANY	(79,079,000)	44,327,000	(151,392,000)
LESS—EFFECT OF PARTICIPATING SHARE-BASED AWARDS	0	(874,000)	0
NET INCOME (LOSS) ATTRIBUTABLE TO THE COMPANY’S COMMON STOCKHOLDERS	$ (79,079,000)	$ 43,453,000	$ (151,392,000)
Net income (loss) per share attributable to common stockholders:
Basic (in dollars per share)	$ (2.04)	$ 1.06	$ (3.44)
Diluted (in dollars per share)	$ (2.04)	$ 1.06	$ (3.44)
Weighted-average shares used to compute net income (loss) per share attributable to common stockholders:
Basic (in shares)	38,731,015	40,897,549	43,958,803
Diluted (in shares)	38,731,015	40,902,860	43,958,803

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (79,079)	$ 44,713	$ (151,710)
Foreign currency translation adjustments	6,029	(1,848)	(5,022)
Other comprehensive income (loss)	6,029	(1,848)	(5,022)
Comprehensive income (loss)	(73,050)	42,865	(156,732)
Less—Comprehensive loss attributable to noncontrolling interest	0	(106)	(1,013)
Comprehensive income (loss) attributable to the Company	$ (73,050)	$ 42,971	$ (155,719)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Common Stock- Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock	Noncontrolling Interest
Beginning Balance at Dec. 31, 2014	$ 778,662	$ 4	$ 453,109	$ 321,083	$ (11)	$ (4,412)	$ 8,889
Beginning Balance (in shares) at Dec. 31, 2014		44,422,881
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock	412		412
Issuance of common stock (in shares)		37,966
Issuance of common stock in acquisitions (net of issuance costs)	15,310		15,310
Issuance of common stock in acquisitions (net of issuance costs) (in shares)		1,675,000
Conversion of restricted stock units to common stock (net of shares of treasury stock purchased)	(854)					(854)
Conversion of restricted stock units to common stock (net of shares of treasury stock purchased) (in shares)		295,089
Treasury stock activity	(23,473)					(23,473)
Treasury stock activity (in shares)		(2,593,222)
Acquisition of noncontrolling interest	(4,828)						(4,828)
Stock compensation expense	5,161		5,161
Comprehensive income (loss) items	(5,011)				(3,998)		(1,013)
Net income (loss)	(151,710)			(151,392)			(318)
Other	341		375	(11)		(23)
Ending Balance at Dec. 31, 2015	614,010	$ 4	474,367	169,680	(4,009)	(28,762)	2,730
Ending Balance (in shares) at Dec. 31, 2015		43,837,714
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock	316		316
Issuance of common stock (in shares)		33,973
Issuance of common stock in acquisitions (net of issuance costs)	4,051	$ 1	4,050
Issuance of common stock in acquisitions (net of issuance costs) (in shares)		500,000
Conversion of restricted stock units to common stock (net of shares of treasury stock purchased)	(767)					(767)
Conversion of restricted stock units to common stock (net of shares of treasury stock purchased) (in shares)		180,049
Partial termination of capped call options (inclusive of tax impact of $116)	1,863		1,863
Convertible debt extinguishment impact (net of tax impact)	(5,560)		(5,560)
Treasury stock activity	(52,295)					(52,295)
Treasury stock activity (in shares)		(5,998,323)
Acquisition of noncontrolling interest	(179)						(179)
Stock compensation expense	5,896		5,896
Comprehensive income (loss) items	(1,874)		(26)		(1,742)		(106)
Net income (loss)	44,713			44,327			386
Ending Balance at Dec. 31, 2016	610,174	$ 5	480,906	214,007	(5,751)	(81,824)	2,831
Ending Balance (in shares) at Dec. 31, 2016		38,553,413
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of restricted stock units to common stock (net of shares of treasury stock purchased)	(872)					(872)
Conversion of restricted stock units to common stock (net of shares of treasury stock purchased) (in shares)		210,611
Settlement of stock appreciation rights in common stock (net of shares of treasury stock purchased)	(385)					(385)
Settlement of stock appreciation rights in common stock (net of shares of treasury stock purchased) (in shares)		73,725
Acquisition of noncontrolling interest	(3,102)		(271)				(2,831)
Impact of 2036 Senior Notes conversion liability reclassification, net of tax	27,908		27,908
Stock compensation expense	6,909		6,909
Comprehensive income (loss) items	6,029				6,029
Net income (loss)	(79,079)			(79,079)
Ending Balance at Dec. 31, 2017	$ 567,582	$ 5	$ 515,452	$ 134,928	$ 278	$ (83,081)	$ 0
Ending Balance (in shares) at Dec. 31, 2017		38,837,749

Consolidated Statements of Sto7

Consolidated Statements of Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Conversion of restricted stock units to common stock, treasury shares purchased	71,112	69,307	92,608
Partial termination of capped call options, tax impact		$ 116
Convertible debt extinguishment impact, tax impact		$ 2,144
Tax impact of 2036 Senior Notes conversion liability reclassification	$ 18,025
Treasury Stock | Stock appreciation rights
Settlement of stock appreciation rights in common stock, treasury stock purchased	35,955

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	3 Months Ended								12 Months Ended			21 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)									$ (79,079,000)	$ 44,713,000	$ (151,710,000)
Adjustments to reconcile net income (loss) to net cash flows from operating activities:
Depreciation expense									34,283,000	31,825,000	24,997,000
Amortization expense of assets and liabilities, net									2,653,000	1,052,000	570,000
Accretion of asset retirement obligations									62,000	78,000	72,000
Accretion of convertible note discount									5,413,000	5,147,000	4,699,000
Accretion of marketable securities									0	0	189,000
Impairment of property, plant and equipment, net	$ 48,532,000	$ 0	$ 1,341,000	$ 0	$ 17,893,000	$ 0	$ 0	$ 0	49,873,000	17,893,000	0
Provision for doubtful accounts									139,000	630,000	(803,000)
Stock compensation expense									6,909,000	5,896,000	5,161,000
Impairment of goodwill									0	0	175,028,000
Impairment of investment									0	0	1,915,000
Deferred tax expense (benefits)									(30,088,000)	3,009,000	(8,953,000)
Change in fair value of contingent consideration									2,484,000	7,904,000	(359,000)
Gain on involuntary conversion	(4,387,000)	$ (942,000)							(5,329,000)	(9,894,000)	0	$ (8,010,000)
Bargain purchase gain									0	0	(5,358,000)
Change in fair value of convertible debt conversion liability									18,833,000	(13,045,000)	0
Gain on debt extinguishment									0	(2,331,000)	0
Other									247,000	(70,000)	(231,000)
Changes in asset and liabilities, net of effects from mergers and acquisitions:
Accounts receivable									74,609,000	145,068,000	(20,309,000)
Inventories									12,029,000	(58,551,000)	29,631,000
Prepaid expenses and other assets									(12,840,000)	(5,566,000)	16,315,000
Accounts payable									(20,198,000)	(133,139,000)	32,422,000
Accrued expenses and other liabilities									(19,375,000)	7,771,000	(6,769,000)
Deferred revenue									(25,028,000)	26,913,000	(16,347,000)
Net cash flows provided from operating activities									15,597,000	75,303,000	80,160,000
CASH FLOWS FROM INVESTING ACTIVITIES:
Cash paid for marketable securities									0	0	(52,435,000)
Cash receipts from marketable securities									0	0	68,979,000
Cash paid for purchase of property, plant and equipment									(67,572,000)	(60,705,000)	(64,477,000)
Insurance proceeds for asset impairments									8,000,000	10,949,000	11,027,000
Transfer into restricted cash									0	0	(4,000,000)
Transfer out of restricted cash									4,000,000	1,960,000	15,845,000
Cash paid for investments									(816,000)	(3,249,000)	(1,452,000)
Cash paid for acquisitions and additional interests, net of cash acquired									(3,482,000)	(12,720,000)	(41,409,000)
Net cash flows used in investing activities									(59,870,000)	(63,765,000)	(67,922,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net borrowings on line of credit									8,025,000	26,445,000	6,470,000
Borrowing on other lines of credit									8,812,000	10,185,000	0
Repayments on other lines of credits									(4,442,000)	(2,437,000)	0
Cash received for issuance of debt									23,575,000	11,775,000	104,000
Cash received on convertible debt									0	152,000,000	0
Cash paid on debt									(14,950,000)	(74,562,000)	(6,708,000)
Cash paid for debt issuance costs									(1,062,000)	(6,369,000)	(542,000)
Cash received on partial termination of capped call options									0	159,000	0
Cash paid for treasury stock									0	(51,474,000)	(24,350,000)
Cash paid for contingent consideration									(14,659,000)	(7,548,000)	(2,248,000)
Cash paid for conversion of restricted stock units and stock appreciation rights									(1,257,000)	0	0
Net cash flows provided from (used in) financing activities									4,042,000	58,174,000	(27,274,000)
NET CHANGE IN CASH AND CASH EQUIVALENTS									(40,231,000)	69,712,000	(15,036,000)
CASH AND CASH EQUIVALENTS, Beginning of period				$ 116,210,000				$ 47,081,000	116,210,000	47,081,000	63,516,000
Effect of exchange rate changes on cash									1,648,000	(583,000)	(1,399,000)
CASH AND CASH EQUIVALENTS, End of period	77,627,000				116,210,000				77,627,000	116,210,000	47,081,000	116,210,000
SUPPLEMENTAL DISCLOSURES OF CASH FLOWS INFORMATION:
Cash paid (received) for income taxes									252,000	410,000	(189,000)
Cash paid for interest									11,637,000	9,920,000	6,947,000
SUPPLEMENTAL DISCLOSURE OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Common stock repurchased included in accrued expenses and other liabilities									0		464,000
Amounts included in period-end accounts payable for:
Purchases of property, plant and equipment									7,688,000	3,833,000	7,734,000
Issuance costs									29,000	250,000	84,000
Incentive common stock liability for supply agreement									0		316,000
Issuance of common stock for acquisitions									0	4,050,000	15,310,000
Contingent consideration for acquisitions									0	4,500,000	5,000,000
Debt assumed in acquisition	$ 0				$ 0				0	0	5,225,000	$ 0
Release of restricted cash to pay off the GOZone Bonds									0	101,315,000	0
Repayment of GOZone Bonds									0	100,000,000	0
Non-cash transfer of line of credit to long-term debt									0	4,498,000	0
Non-cash allocation of proceeds from the 2036 Convertible Notes issuance to convertible debt conversion liability									0	40,145,000	0
Non-cash allocation of purchase price between debt and equity related to the repurchase of the 2019 Convertible Notes									0	7,387,000	0
Non-cash reclassification of the 2036 Convertible Notes conversion liability to additional paid in capital, net of tax impact of $18,025									27,908,000	0	0
Non-cash share repurchases from partial capped call termination									0	1,588,000	0
Accruals of insurance proceeds related to impairment of property, plant and equipment									$ 0	$ 313,000	$ 1,414,000

Consolidated Statements of Cas9

Consolidated Statements of Cash Flows (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)
Statement of Cash Flows [Abstract]
Tax impact of non-cash reclassification of the 2036 Convertible Notes conversion liability to additional paid in capital	$ 18,025

Organization, Presentation, and

Organization, Presentation, and Nature of the Business	12 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization, Presentation, and Nature of the Business	ORGANIZATION, PRESENTATION, AND NATURE OF THE BUSINESS Renewable Energy Group, Inc. (the "Company" or "REG") is a company focused on providing cleaner, lower carbon products and services. Today, the Company principally generates revenue as a leading North American advanced biofuels producer with a nationwide distribution and logistics system. The Company participates in each aspect of biomass-based diesel production, from acquiring feedstock, managing construction and operating biomass-based diesel production facilities, to marketing, selling and distributing biomass-based diesel and its co-products. To do this, REG utilizes this nationwide production, distribution and logistics system as part of an integrated value chain model to focus on converting natural fats, oils and greases into advanced biofuels and converting diverse feedstocks into renewable chemicals. As of December 31, 2017, the Company owns and operates fourteen biorefineries, with twelve locations in North America and two locations in Europe, which includes thirteen operating biomass-based diesel production facilities with aggregate nameplate production capacity of 520 million gallons per year, or mmgy, and one fermentation facility. REG has one feedstock processing facility. The Company's network includes the addition of a 20 -million gallon nameplate capacity biomass-based diesel refinery located in DeForest, Wisconsin, acquired in March 2016. Ten of these plants are “multi-feedstock capable” which allows them to use a broad range of lower cost feedstocks, such as inedible corn oil, used cooking oil and inedible animal fats in addition to vegetable oils, such as soybean oil and canola oil. The Company also has three partially constructed production facilities and one non-operational production facility. The Company will need to raise additional capital to complete construction of these plants and fund working capital requirements. It is uncertain when financing will be available. During fourth quarter 2017, the Company wrote down the carrying value at its New Orleans facility to its estimated salvage value due to the probability of that project being completed in the near term is unlikely as a result of strategic investment priorities, such as potential renewable diesel expansions at Geismar, coupled with financing unattractiveness and construction cost requirements. The biomass-based diesel industry and the Company’s business have benefited from the continuation of certain federal and state incentives. The federal biodiesel mixture excise tax credit (the "BTC") was reinstated for 2015, in effect throughout 2016 and lapsed on January 1, 2017. The 2017 BTC was reinstated on February 9, 2018. It is uncertain whether the BTC will be reinstated for 2018 or thereafter. The expiration along with other amendments of any one or more of those laws, could adversely affect the financial results of the Company.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Consolidation The consolidated financial statements include the accounts of the Company, its wholly-owned subsidiaries, and entities which it controls. All intercompany balances and transactions have been eliminated for consolidated reporting purposes. Cash and Cash Equivalents Cash and cash equivalents consists of money market funds and demand deposits with financial institutions. The Company considers all highly liquid debt instruments purchased with an original maturity of three months or less to be cash equivalents. Accounts Receivable Accounts receivable are carried at invoiced amount less allowance for doubtful accounts. Management estimates the allowance for doubtful accounts based on existing economic conditions, the financial conditions of customers and the amount and age of past due accounts. Receivables are considered past due if full payment is not received by the contractual due date. Past due accounts are generally written off against the allowance for doubtful accounts only after reasonable collection attempts have been exhausted. Activity regarding the allowance for doubtful accounts was as follows: Balance, January 1, 2015 $ 2,273 Amount charged to selling, general and administrative expenses (803 ) Charge-offs, net of recoveries (119 ) Balance, December 31, 2015 1,351 Amount charged to selling, general and administrative expenses 630 Charge-offs, net of recoveries (106 ) Balance, December 31, 2016 1,875 Amount charged to selling, general and administrative expenses 139 Charge-offs, net of recoveries (779 ) Balance, December 31, 2017 $ 1,235 Through December 31, 2017 , the Company has received approximately $86,504 of the $89,266 outstanding related to the 2016 biodiesel mixture excise tax credit, which results in $2,762 remaining as outstanding receivables at December 31, 2017 . Inventories Inventories are valued at the lower of cost or net realizable value. Cost is determined based on the first-in, first-out method. There were no lower of cost or market adjustments made to the inventory values reported as of December 31, 2017 and 2016 . Renewable Identification Numbers (RINs) When the Company produces and sells a gallon of biomass-based diesel, 1.5 to 1.7 RINs per gallon are generated. RINs are used to track compliance with Renewable Fuel Standards (RFS2). RFS2 allows the Company to attach between zero and 2.5 RINs to any gallon of biomass-based diesel. As a result, a portion of the selling price for a gallon of biomass-based diesel is generally attributable to RFS2 compliance. However, RINs that the Company generates are a form of government incentive and not a result of the physical attributes of the biomass-based diesel production. Therefore, no cost is allocated to the RIN when it is generated, regardless of whether the RIN is transferred with the biomass-based diesel produced or held by the Company pending attachment to other biomass-based diesel production sales. In addition, the Company also obtains RINs from third parties who have separated the RINs from gallons of biomass-based diesel. From time to time, the Company holds varying amounts of these separated RINs for resale. RINs obtained from third parties are initially recorded at their cost and are subsequently revalued at the lower of cost or market as of the last day of each accounting period and the resulting adjustments are reflected in costs of goods sold for the period. The value of these RINs is reflected in “Prepaid expenses and other assets” on the consolidated balance sheet. The cost of goods sold related to the sale of these RINs is determined using the average cost method, while market prices are determined by RIN values, as reported by the Oil Price Information Service (OPIS). California’s Low Carbon Fuel Standard The Company generates Low Carbon fuel Standard (LCFS) credits for its low carbon fuels or blendstocks when its qualified low carbon fuels are imported by REG to California though approved physical pathways. LCFS credits are used to track compliance with California’s LCFS, which enables the Company to generate LCFS credits based upon the carbon intensity of qualified fuels that are imported by REG into California. Other companies can take title outside of California and generate LCFS credits instead of REG upon import into the state. One LCFS credit equates to one metric ton reduction of carbon dioxide compared to the petroleum fuel baseline so the amount of gallons of low carbon fuel consumption to generate one credit will vary. As a result, a portion of the selling price for a gallon of biomass-based diesel sold into California is also attributable to LCFS compliance. However, LCFS credits that the Company generates are a form of government incentive and not a result of the physical attributes of the biomass-based diesel production. Therefore, no cost is allocated to the LCFS credit when it is generated, regardless of whether the LCFS credit is transferred with the biomass-based diesel produced or held by the Company on other biomass-based diesel sales that do not transfer credits. In addition, the Company also obtains LCFS credits from third party trading activities. From time to time, the Company holds varying amounts of these third party LCFS credits for resale. LCFS credits obtained from third parties is initially recorded at their cost and are subsequently revalued at the lower of cost or net realizable value as of the last day of each accounting period and the resulting adjustments are reflected in costs of goods sold for the period. The value of LCFS obtained from third parties is reflected in “Prepaid expenses and other assets” on the consolidated balance sheet. The cost of goods sold related to the sale of these LCFS credits is determined using the average cost method, while market prices are determined by LCFS values, as reported by the Oil Price Information Service (OPIS). At December 31, 2017 and 2016, the Company held no LCFS credits purchased from third parties. The Company records assets acquired and liabilities assumed through the exchange of non-monetary assets based on the fair value of the assets and liabilities acquired or the fair value of the consideration exchanged, whichever is more readily determinable. Derivative Instruments Derivatives are recorded on the balance sheet at fair value with changes in fair value recognized in current period earnings. The Company did not elect to use hedge accounting during the periods presented. Property, Plant and Equipment Property, plant and equipment is recorded at cost less accumulated depreciation. Maintenance and repairs are expensed as incurred. Depreciation expense is computed on a straight-line method based upon estimated useful lives of the assets. Estimated useful lives are as follows: Automobiles and trucks 5 years Computers and office equipment 5 years Office furniture and fixtures 7 years Machinery and equipment 5-30 years Leasehold improvements the lesser of the lease term or 30 years Buildings and improvements 30-40 years In June 2017, the Company experienced a fire at its Madison facility, resulting in the shutdown of the facility. Through December 31, 2017, the Company impaired fixed assets with a total net book value of approximately $2,671 as a result of the fire in June 2017. During the year ended December 31, 2017, the Company received payments in the amounts of $8,000 and $2,000 to cover initial costs incurred for property losses and business interruption, respectively. In June 2017, the Company entered into an agreement to terminate the ground lease and purchase the land it had leased for its Geismar, Louisiana biorefinery as well as more than 61 adjacent acres from Lion Copolymer for $20,000 . The Company recorded a loss of $3,967 as a result of the lease termination in June 2017. During the years ended December 31, 2017 , 2016 and 2015 , the Company capitalized interest incurred on debt during the construction of assets of $301 , $537 and $897 , respectively. Goodwill Goodwill is tested for impairment annually on July 31 or when impairment indicators exist. Goodwill is allocated and tested for impairment by reporting units. At December 31, 2017 and 2016, the Company had goodwill in the Services reporting unit. The annual impairment test at July 31, 2017 determined that the fair value of the Services reporting unit exceeded its carrying value by approximately 49% . No impairment of goodwill was recorded during the years ended December 31, 2017 and 2016. During 2015, the Company had a full write-off of goodwill in the Biomass-based Diesel and Renewable Chemicals reporting units. Impairment of Long-lived Assets The Company tests its long-lived assets for recoverability when events or circumstances indicate that its carrying amount may not be recoverable. Significant assumptions used in the undiscounted cash flow analysis, when it is required, include the projected demand for biomass-based diesel based on annual renewable fuel volume obligations under the Renewable Fuel Standards (RFS2), the Company's capacity to meet that demand, the market price of biomass-based diesel and the cost of feedstock used in the manufacturing process. For facilities under construction, estimates also include the capital expenditures necessary to complete construction of the plant and the projected costs of financing. During the fourth quarter of 2017, the Company recorded impairment charges of $44,649 related to its New Orleans facility's property, plant and equipment assets resulting from the probability of that project being completed in the near future is unlikely as a result of strategic investment priorities, such as potential renewable diesel expansions at Geismar, coupled with financing unattractiveness and construction cost requirements. The impairment charge reflected the difference between the carrying amount and the estimated salvage value. The salvage value was determined based on the cost approach, which placed emphasis on the cost to replace or reproduce the asset. The basic steps of the cost approach included (1) estimate the replacement/reproduction cost new; (2) estimate physical depreciation; (3) estimate functional and economic obsolescence, if any; and (4) conclude the fair value of the asset. The determination of the salvage value represented a Level 3 asset measured at fair value on a nonrecurring basis subsequent to its original recognition. In addition, the Company recorded impairment charges of $5,224 against certain property, plant and equipment as the carrying amounts of these assets were deemed not recoverable given the assets' deteriorating physical conditions identified during 2017. In 2016, impairment charges amounting to $15,593 and $2,300 were recorded related to the Company's Emporia facility's property, plant and equipment assets and certain other plant, property and equipment. Convertible Debt In June 2016, the Company issued $152,000 aggregate principal amount of 4% convertible senior notes due 2036 (the "2036 Convertible Notes"). The Company could not elect to issue shares of common stock upon conversion of the 2036 Convertible Notes to the extent such election would result in the issuance of more than 19.99% of the common stock outstanding immediately before the issuance of the 2036 Convertible Notes until the Company received stockholder approval for such issuance. As a result, the embedded conversion option was accounted for as an embedded derivative liability. On December 8, 2017, at the special meeting of stockholders, the Company obtained the approval from its stockholders to remove the common stock issuance restrictions in connection with conversions of the 2036 Convertible Notes. Accordingly, the embedded conversion option after being fair valued at $45,933 and net of tax of $18,025 , has been reclassified into Additional Paid-in Capital at December 8, 2017. Fair value adjustments related to this liability of $18,833 were recorded for the year ended December 31, 2017 . See "Note 10 - Debt" for a further description of the transaction. Capped Call Transaction In connection with the issuance of the 2014 convertible senior notes, the Company entered into capped call transactions. The purchased capped call transactions were recorded as a reduction to common stock-additional paid-in-capital. Because this was considered to be an equity transaction and qualifies for the derivative scope exception, no future changes in the fair value of the capped call will be recorded by the Company. During 2016, in connection with the issuance of the 2036 Convertible Notes, certain call options covered by the original capped call transaction were rebalanced and reset to cover 100% of the total number of shares of the Company's Common Stock underlying the remaining principal of the 2019 Convertible Notes. The impact of these transactions, net of tax, was reflected as an addition/reduction to common stock-additional paid-in capital as presented in the Consolidated Statements of Stockholders' Equity. Security Repurchase Programs In December 2017, the Company's board of directors approved a repurchase program of up to $75,000 of the Company's convertible notes and/or shares of common stock. Under the program, the Company may repurchase convertible notes or shares from time to time in open market transactions, privately negotiated transactions or by other means. The timing and amount of repurchase transactions were determined by the Company's management based on its evaluation of market conditions, share price, bond price, legal requirements and other factors. No repurchases have been made under this program during 2017. Foreign Currency Transactions and Translation The Company’s reporting and functional currency is U.S. dollars. Monetary assets and liabilities denominated in currencies other than U.S. dollars are remeasured into their respective functional currencies at exchange rates in effect at the balance sheet date. The resulting exchange gain or loss is included in the Company’s Consolidated Statements of Operations as foreign exchange gain (loss) unless the remeasurement gain or loss relates to an intercompany transaction that is of a long-term investment nature and for which settlement is not planned or anticipated in the foreseeable future. Gains or losses arising from translation of such transactions are reported as a component of accumulated other comprehensive income (loss) in the Company’s Consolidated Balance Sheets. The Company translates the assets and liabilities of its foreign subsidiaries from their respective functional currencies to U.S. dollars at the appropriate spot rates as of the balance sheet date. Generally, the Company's foreign subsidiaries use the local currency as their functional currency. Changes in the carrying value of these assets and liabilities attributable to fluctuations in spot rates are recognized in foreign currency translation adjustment, a component of accumulated other comprehensive income (loss) in the Company’s Consolidated Balance Sheets. The other comprehensive loss amounts presented in the Company's Consolidated Statements of Comprehensive Income (Loss) and Consolidated Statements of Stockholders' Equity mainly include the foreign currency translation adjustment resulting from translating the financial statements of certain subsidiaries from Euros to US Dollars, the Company's functional currency. Revenue Recognition The Company recognizes revenues from the following sources: • the sale of biomass-based diesel and its co-products, as well as Renewable Identification Numbers (RINs), California Low Carbon Fuel Standard credits (LCFS credits) and raw material feedstocks, purchased or produced by the Company at owned manufacturing facilities and manufacturing facilities with which the Company has tolling arrangements; • the resale of biomass-based diesel, RINs, LCFS credits and raw material feedstocks acquired from third parties; • the sale of petroleum-based heating oil and diesel fuel acquired from third parties, along with the sale of these items further blended with biodiesel produced at wholly owned facilities; • incentives received from federal and state programs for renewable fuels; and • fees received for the marketing and sales of biomass-based diesel produced by third parties and from managing operations of third party facilities. Biomass-based diesel, including RINs and LCFS credits, and raw material feedstock revenues are recognized where there is persuasive evidence of an arrangement, delivery has occurred, the price has been fixed or is determinable and collectability can be reasonably assured. Fees received under toll manufacturing agreements with third parties are generally established as an agreed upon amount per gallon of biomass-based diesel produced. The fees are recognized where there is persuasive evidence of an arrangement, delivery has occurred, the price has been fixed or is determinable and collectability can be reasonably assured. Revenues associated with the governmental incentive programs are recognized when the amount to be received is determinable, collectability is reasonably assured and the sale of product giving rise to the incentive has been recognized. The Company received funds from the United States Department of Agriculture (USDA) in the amount of $607 , $434 and $624 for the years ended December 31, 2017 , 2016 and 2015 , respectively. The Company records amounts when it has received notification of a payment from the USDA or is in receipt of the funds and records the awards under the Program in "Biomass-based diesel government incentives" as they are closely associated with the Company's biomass-based diesel production activities. Freight Amounts billed to customers for freight are included in biomass-based diesel sales. Costs incurred for freight are included in costs of goods sold. Advertising Costs Advertising costs are charged to expense as they are incurred. Advertising and promotional expenses were $2,140 , $1,746 and $1,288 for the years ended December 31, 2017 , 2016 and 2015 , respectively. Research and Development Research and development (R&D) costs are charged to expense as incurred. In process research and development (IPR&D) assets acquired in connection with acquisitions are recorded on the Consolidated Balance Sheets as intangible assets. The Company determined the useful life of the IPR&D assets to be 15 years and utilizes a straight line method to amortize these assets over the useful life. No impairment was identified related to the Company's IPR&D balance at December 31, 2017, 2016 and 2015. Employee Benefits Plan The Company sponsors an employee savings plan under Section 401(k) of the Internal Revenue Code. The Company makes matching contributions equal to 50% of the participant’s pre-tax contribution up to a maximum of 6% of the participant’s eligible earnings. Total expense related to the Company’s defined contribution plan was $1,367 , $1,168 and $1,071 for the years ended December 31, 2017 , 2016 and 2015 , respectively. Stock-Based Compensation Stock-based compensation expense is measured at the grant-date fair value of the award and recognized as compensation expense over the vesting period. Income Taxes The Company’s income tax provision, deferred income tax assets and liabilities, and liabilities for uncertain tax benefits represent the company’s best estimate of current and future income taxes to be paid. The annual tax rate is based on income tax laws, statutory tax rates, taxable income levels and tax planning opportunities available in various jurisdictions where the company operates. These tax laws are complex and require significant judgment to determine the consolidated provision for income taxes. Changes in tax laws, statutory tax rates and estimates of the company’s future taxable income levels could result in actual realization of deferred taxes being materially different from amounts provided for in the consolidated financial statements. The indefinite reinvestment in the earnings of non-US subsidiaries assertion is determined by management’s judgment about and intentions concerning future investment in operations. As of December 31, 2017, the Company is provisionally no longer indefinitely reinvested in the earnings of non-US subsidiaries. Concentrations One customer represented slightly less than 10% of the total consolidated revenues of the Company for the years ended December 31, 2017 , 2016 and 2015 . All customer amounts disclosed in the table are related to biomass-based diesel sales: 2017 2016 2015 Customer A $ 182,236 $ 144,849 $ 114,030 The Company maintains cash balances at financial institutions, which may at times exceed the $250 coverage by the U.S. Federal Deposit Insurance Company. Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the dates of the financial statements and reported amounts of revenues and expenses during the reporting periods. These estimates are based on information that is currently available to management and on various assumptions that the Company believes to be reasonable under the circumstances. Actual results could differ from those estimates. New Accounting Pronouncements On February 25, 2016, the FASB issued ASU 2016-02, which introduces a lessee model that brings most leases on the balance sheet. The new standard also aligns many of the underlying principles of the new lessor model with those in ASC 606, the FASB’s new revenue recognition standard (e.g., those related to evaluating when profit can be recognized). Furthermore, the ASU addresses other concerns related to the current leases model. The ASU is effective for annual periods beginning after December 15, 2018 and interim periods therein. The Company has started the process to compile and review all of its leases. While the Company is continuing to assess all potential impacts of the standard, the Company currently believes the most significant impact relates to the classifications of its accounting for office, railcar and terminal operating leases. The Company plans to apply a modified retrospective transition approach to each applicable lease that exists at January 1, 2017 as well as leases entered after this date. In March 2016, the FASB issued ASU 2016-08, "Revenue from Contracts with Customers (Topic 606): Principal versus Agent Consideration (Reporting Revenue Gross versus Net)" which clarifies how an entity should identify the unit of accounting for the principal versus agent evaluation and how it should apply the control principle to certain types of arrangements, such as service transactions. The guidance also re-frames the indicators to focus on evidence that an entity is acting as a principal rather than an agent. The guidance is effective for public business entities for fiscal years beginning after December 15, 2017 and interim periods within those fiscal years. The Company has evaluated the impact of this guidance and does not expect it to have any material impact on its consolidated financial statements. In May 2016, the FASB issued ASU 2016-12, which amends certain aspects of the new revenue standard, ASU 2014-09. The amendments address issues such as collectability; presentation of sales tax and other similar taxes collected from customers; noncash consideration; contract modifications and completed contracts at transition; and transition technical correction. The guidance is effective for public business entities for fiscal years beginning after December 15, 2017 and interim periods within those fiscal years. The Company has evaluated the impact of this guidance and does not expect it to have any material impact on its consolidated financial statements. Effective January 1, 2018, the Company will be required to adopt the new guidance of ASC Topic 606, Revenue from Contracts with Customers (Topic 606), which will supersede the revenue recognition requirements in ASC Topic 605, Revenue Recognition. Topic 606 requires the Company to recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The new guidance requires us to apply the following steps: (1) identify the contract with a customer; (2) identify the performance obligations in the contract; (3) determine the transaction price; (4) allocate the transaction price to the performance obligations in the contract; and (5) recognize revenue when, or as, the Company satisfies a performance obligation. The Company has substantially completed our impact assessment and determined that the majority of its contracts will continue to be recognized at a point in time and that the number of performance obligations and the accounting for variable consideration are not expected to be significantly different from current practice. Additionally, the Company will adopt Topic 606 on a modified retrospective basis, which is not expected to result in any material cumulative effect adjustments to retained earnings and provide additional disclosures of the amount by which each financial statement line item is affected in the current reporting period, as compared to the guidance that was in effect before the change, and an explanation of the reasons for significant changes. The adoption of this new guidance will require expanded disclosures in its consolidated financial statements. On June 16, 2016, the FASB issued ASU 2016-13, which amends the Board’s guidance on the impairment of financial instruments. The ASU adds to U.S. GAAP an impairment model (known as the current expected credit loss (CECL) model) that is based on expected losses rather than incurred losses. Under the new guidance, an entity recognizes as an allowance its estimate of expected credit losses. For public companies, the ASU is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. The Company is evaluating the impact of this guidance, but does not expect it to have any material impact on its consolidated financial statements. The FASB issued ASU 2016-18 on November 17, 2016 to add or clarify guidance on the classification and presentation of restricted cash in the statement of cash flows. For public companies , the guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The Company has evaluated the impact of this guidance and determined that it will not have any material impact on its consolidated financial statements. On August 28, 2017, the FASB issued ASU 2017-12, which amends the hedge accounting recognition and presentation requirements in ASC 815. The ASU was issued to improve the transparency and understandability of information conveyed to financial statement users about an entity’s risk management activities by better aligning the entity’s financial reporting for hedging relationships with those risk management activities and reduce the complexity of and simplify the application of hedge accounting by preparers. the ASU is effective for public companies for fiscal years beginning after December 15, 2018, and interim periods therein. The Company is evaluating the impact of this ASU on its consolidated financial statements.

Stockholders' Equity of the Com

Stockholders' Equity of the Company	12 Months Ended
	Dec. 31, 2017
Stockholders' Equity Attributable to Parent [Abstract]
Stockholders' Equity of the Company	STOCKHOLDERS’ EQUITY OF THE COMPANY Common Stock The Company has authorized capital stock consisting of 450,000,000 shares, all with a par value of $.0001 per share, which includes 300,000,000 shares of Common Stock, 140,000,000 shares of Common Stock A and 10,000,000 shares of Preferred Stock including 3,000,000 shares of Series B Preferred Stock. Each holder of Common Stock is entitled to one vote for each share of Common Stock held on all matters submitted to a vote of stockholders. Subject to preferences that may apply to shares of previously outstanding Series A Preferred Stock and currently outstanding Series B Preferred Stock as outlined below, the holders of outstanding shares of Common Stock are entitled to receive dividends. After the payment of all preferential amounts required to the holders of Series B Preferred Stock, all of the remaining assets of the Company available for distribution shall be distributed ratably among the holders of Common Stock.

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
Acquisitions	ACQUISITIONS 2016 Acquisition Sanimax Energy, LLC On March 15, 2016, the Company acquired fixed assets and inventory from Sanimax Energy, including the 20 mmgy nameplate capacity biomass-based diesel refinery in DeForest, Wisconsin. The Company completed its initial accounting of this business combination as the valuation of the real and personal property was finalized as of September 30, 2016. The following table summarizes the consideration paid for the acquisition from Sanimax Energy: March 15, 2016 Consideration at fair value for acquisition from Sanimax: Cash $ 12,541 Common stock 4,050 Contingent consideration 4,500 Total $ 21,091 The fair value of the 500,000 shares of Common Stock issued was determined using the closing market price of the Company's common shares at the date of acquisition. The Company may pay contingent consideration of up to $5,000 (Earnout Payments) over a 7 -year period after the acquisition, subject to achievement of certain milestones related to the biomass-based diesel gallons produced and sold by REG Madison. The Earnout Payments are payable in cash and cannot exceed $1,700 in any one year period beginning March 15, 2016 through 2023 and up to $5,000 in aggregate. As of December 31, 2017 , the Company has recorded a contingent liability of $2,603 , approximately $1,160 of which has been classified as current on the Consolidated Balance Sheets. The following table summarizes the fair values of the assets acquired at the acquisition date. March 15, 2016 Assets (liabilities) acquired from Sanimax Energy: Inventory $ 1,591 Property, plant and equipment 19,500 Total identifiable assets acquired 21,091 Accrued expenses and liabilities — Net identifiable assets acquired $ 21,091 The following unaudited pro forma condensed combined results of operations assume that the Sanimax Energy acquisition was completed as of January 1, 2015 and as if the stock had been issued on the same date. Year ended December 31, 2017 Year ended December 31, 2016 Year ended December 31, 2015 Revenues $ 2,158,243 $ 2,049,658 $ 1,406,580 Net income (loss) attributable to the Company's common stockholders (79,079 ) 43,453 (157,524 ) Basic net income (loss) per share attributable to common stockholders $(2.04) $1.06 $(3.50) 2015 acquisitions Imperium Renewables, Inc. On August 19, 2015, the Company acquired substantially all the assets of Imperium Renewables, Inc. (Imperium), including the 100 -mmgy nameplate biomass-based diesel refinery and deepwater port terminal at the Port of Grays Harbor, Washington. The results of Imperium's operations have been included in the consolidated financial statements since that date. The Company has finalized its accounting of this business combination during the fourth quarter of 2015. The following table summarizes the consideration paid for Imperium: August 19, 2015 Consideration at fair value for Imperium: Cash $ 36,748 Common stock 15,310 Contingent consideration 5,000 Total $ 57,058 The fair value of the 1,675,000 shares of Common Stock issued to Imperium was determined using the closing market price of the Company's common shares at the date of acquisition. Subject to achievement of certain milestones related to the biomass-based diesel gallons produced and sold by REG Grays Harbor and whether the BTC is reinstated, Imperium may receive certain contingent consideration (Earnout Payments) over a two -year period after the acquisition. The Earnout Payments were paid in cash. As of December 31, 2017 , the Company has paid off all contingent liability to Imperium. The following table summarizes the estimated fair values of the assets acquired and liabilities assumed at the acquisition date. August 19, 2015 Assets (liabilities) acquired of Imperium: Cash $ 168 Accounts receivable 8,274 Inventory 18,989 Other current assets 87 Property, plant and equipment 46,476 Intangible assets 2,900 Total identifiable assets acquired 76,894 Accounts payable (4,828 ) Accrued expenses and other liabilities (942 ) Debt (5,225 ) Deferred tax liabilities (3,483 ) Total liabilities assumed (14,478 ) Net identifiable assets acquired 62,416 Less: Bargain purchase gain 5,358 Net assets acquired $ 57,058 Imperium was acquired at a price less than fair value of the net identifiable assets, and the Company recorded a net of tax bargain purchase gain of $5,358 . All future adjustments will be reported in the Consolidated Statements of Operations. The bargain purchase gain is reported in the "Other Income, Net" on the Consolidated Statements of Operations. Prior to recognizing a bargain purchase gain, the Company reassessed whether all assets acquired and liabilities assumed had been correctly identified as well as the key valuation assumptions and business combination accounting procedures for this acquisition. After careful consideration and review, the Company concluded that the recognition of a bargain purchase gain was appropriate for this acquisition. Factors that contributed to the bargain purchase price were: • The assets were not fully utilized by the seller and that the transaction was completed with a motivated seller that appeared to have recapitalized its investments and desired to exit the facilities that no longer fit its strategy given the uncertainties in the industry. • The Company was able to complete the acquisition in an expedient manner, with a cash payment, stock issuance and without a financial contingency, which was a key attribute for the seller. The relatively small size of the transaction for the Company, the lack of required third-party financing and the Company's expertise in completing similar transactions in the past gave the seller confidence that the Company could complete the transaction quickly and without difficultly. • Due to the unique nature of the products and limited number of potential buyers for this business, the seller found it advantageous to accept the Company's purchase price based upon our demonstrated ability to operate similar businesses, and financial strength that may enable the Company to make improvement and run the business at increased production rates in the long run.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2017
Inventory Disclosure [Abstract]
Inventories	INVENTORIES Inventories consist of the following at December 31: 2017 2016 Raw materials $ 39,975 $ 34,560 Work in process 3,523 3,775 Finished goods 92,049 107,073 Total $ 135,547 $ 145,408

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	PROPERTY, PLANT AND EQUIPMENT Company's owned property, plant and equipment consists of the following at December 31: 2017 2016 Land $ 10,480 $ 5,412 Building and improvements 140,261 134,398 Leasehold improvements 10,806 10,520 Machinery and equipment 534,991 511,461 696,538 661,791 Accumulated depreciation (175,531 ) (138,372 ) 521,007 523,419 Construction in process 66,390 76,055 Total $ 587,397 $ 599,474 During 2017, the Company recorded impairment charges of $44,649 related to its New Orleans facility's property, plant and equipment assets. In 2016, the Company recorded impairment charges of $15,593 related to the Company's Emporia facility. Refer to Note 2 for further details.

Intangible Assets

Intangible Assets	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	INTANGIBLE ASSETS Amortizing intangible assets consist of the following at December 31: December 31, 2017 Cost Accumulated Amortization Net Weighted Average Remaining Life Raw material supply agreement $ 6,230 $ (2,408 ) $ 3,822 8.0 years Renewable diesel technology 8,300 (1,983 ) 6,317 11.5 years Acquired customer relationships 2,900 (686 ) 2,214 7.6 years Ground lease 200 (141 ) 59 3.9 years In-process research and development 15,956 (1,241 ) 14,715 13.8 years Total intangible assets $ 33,586 $ (6,459 ) $ 27,127 December 31, 2016 Cost Accumulated Amortization Net Weighted Average Remaining Life Raw material supply agreement $ 6,230 $ (1,987 ) $ 4,243 9.0 years Renewable diesel technology 8,300 (1,429 ) 6,871 12.5 years Acquired customer relationships 2,900 (396 ) 2,504 8.6 years Ground lease 200 (127 ) 73 4.9 years In-process research and development 15,956 (177 ) 15,779 14.8 years Total intangible assets $ 33,586 $ (4,116 ) $ 29,470 The raw material supply agreement acquired is amortized over its 15 year term based on actual usage under the agreement and expires in 2025. The Company determined the estimated amount of raw materials to be purchased over the life of the agreement to calculate a per pound rate of consumption. The rate is then multiplied by the actual usage each period for expense reporting purposes. Amortization expense of $2,343 , $1,471 and $1,112 for intangible assets was recorded for the years ended December 31, 2017 , 2016 and 2015 , respectively. Estimated amortization expense for fiscal years ended December 31 is as follows: 2018 $ 2,425 2019 2,433 2020 2,440 2021 2,447 2022 2,441 Thereafter 14,941 Total $ 27,127

Other Assets

Other Assets	12 Months Ended
	Dec. 31, 2017
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Assets	OTHER ASSETS Prepaid expenses and other current assets consist of the following at December 31: 2017 2016 Commodity derivatives and related collateral, net $ 1,610 $ 7,127 Prepaid expenses 11,733 10,665 Deposits 2,899 2,897 RIN inventory 27,028 9,398 Taxes receivable 6,356 4,539 Other 2,254 1,646 Total $ 51,880 $ 36,272 RIN inventory is valued at the lower of cost or net realizable value and consists of (i) RINs the Company generates in connection with its production of biomass-based diesel and (ii) RINs acquired from third parties. RINs generated by the Company are recorded at no cost, as these RINs are government incentives and not a tangible output from its biomass-based diesel production. The cost of RINs acquired from third parties is determined using the average cost method. RIN market value is based upon pricing as reported by the Oil Price Information Service (OPIS). Since RINs generated by the Company have zero cost associated to them, the lower of cost or market adjustment in RIN inventory reflects only the value of RINs obtained from third parties. RIN inventory values were adjusted in the amount of $2,629 and $612 at December 31, 2017 and 2016 , respectively, to reflect the lower of cost or market. Other noncurrent assets consist of the following at December 31: 2017 2016 Spare parts inventory $ 2,764 $ 3,532 Catalysts 2,962 4,479 Deposits 381 2,392 Other 933 2,227 Total $ 7,040 $ 12,630

Accrued Expenses and Other Liab

Accrued Expenses and Other Liabilities	12 Months Ended
	Dec. 31, 2017
Accrued Liabilities [Abstract]
Accrued Expenses and Other Liabilities	ACCRUED EXPENSES AND OTHER LIABILITIES Accrued expenses and other liabilities consist of the following at December 31: 2017 2016 Accrued property taxes $ 1,353 $ 1,518 Accrued employee compensation 8,172 15,005 Accrued interest 590 537 Contingent consideration, current portion 25,545 17,637 Unfavorable lease obligation, current portion 1,129 1,828 Excise tax payable 1,046 1,603 Income tax payable 455 — Other 897 788 Total $ 39,187 $ 38,916 Other noncurrent liabilities consist of the following at December 31: 2017 2016 Severance payable $ 603 $ — Straight-line lease liability 1,801 2,421 Asset retirement obligations 593 1,140 Other 1,117 1,295 Total $ 4,114 $ 4,856

Debt

Debt	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Debt	DEBT Term debt The Company’s term debt at December 31 is as follows: 2017 2016 4.00% Convertible Senior Notes, $152,000 face amount, due in June 2036 $ 116,255 $ 113,446 2.75% Convertible Senior Notes, $73,838 face amount, due in June 2019 69,859 67,254 REG Danville term loan, secured, variable interest rate of LIBOR plus 4%, due in July 2022 11,460 8,163 REG Newton term loan, secured, variable interest rate of LIBOR plus 4%, due in December 2018 8,189 13,063 REG Mason City term loan, fixed interest rate of 5%, due in July 2019 1,153 2,659 REG Ralston term loan, fixed interest rate of 5%, due in October 2025 6,183 — REG Ames term loans, secured, fixed interest rates of 3.5% and 4.25%, due in January 2018 and December 2019, respectively — 3,565 REG Grays Harbor term loan, variable interest of minimum 3.5% or Prime Rate plus 0.25%, due in May 2022 7,882 9,273 REG Capital term loan, fixed interest rate of 3.99%, due in January 2028 7,400 — Other 179 468 Total debt before debt issuance costs 228,560 217,891 Less: Current portion of long-term debt 13,397 15,402 Less: Debt issuance costs (net of accumulated amortization of $3,510 and $2,396, respectively) 6,627 6,286 Total long-term debt $ 208,536 $ 196,203 Convertible Senior Notes On June 2, 2016, the Company issued $152,000 aggregate principal amount of the 2036 Convertible Notes in a private offering to qualified institutional buyers. The 2036 Convertible Notes bear interest at a rate of 4.00% per year payable semi-annually in arrears on June 15 and December 15 of each year, beginning December 15, 2016. The notes will mature on June 15, 2036, unless repurchased, redeemed or converted in accordance with their terms prior to such date. Prior to December 15, 2035, the 2036 Convertible Notes will be convertible only upon satisfaction of certain conditions and during certain periods as stipulated in the indenture. On or after December 15, 2035 until the close of business on the second scheduled trading day immediately preceding the maturity date, holders of the 2036 Convertible Notes may convert their notes at any time. Unless and until the Company obtains stockholder approval under applicable NASDAQ Stock Market rules, the 2036 Convertible Notes will be convertible, subject to certain conditions, into cash. If the Company obtains such stockholder approval, the 2036 Convertible Notes may be settled in cash, the Company’s common shares or a combination of cash and the Company’s common shares, at the Company’s election. The Company may not redeem the 2036 Convertible Notes prior to June 15, 2021. Holders of the 2036 Convertible Notes will have the right to require the Company to repurchase for cash all or some of their notes at 100% of their principal, plus any accrued and unpaid interest on each of June 15, 2021, June 15, 2026 and June 15, 2031. Holders of the 2036 Convertible Notes will have the right to require the Company to repurchase for cash all or some of their notes at 100% of their principal, plus any accrued and unpaid interest upon the occurrence of certain fundamental changes. The initial conversion rate is 92.8074 common shares per $1,000 (one thousand) principal amount of 2036 Convertible Notes (equivalent to an initial conversion price of approximately $10.78 per common share). The net proceeds from the offering of the 2036 Convertible Notes were approximately $147,118 , after deducting fees and offering expenses of $4,882 , which was capitalized as debt issuance costs and is being amortized through June 2036. At issuance date, the Company evaluated the terms of the conversion features under the applicable accounting literature, including Derivatives and Hedging, ASC 815, and determined that a certain feature required separate accounting as a derivative. This derivative was recorded as a long-term liability, "Convertible Debt Conversion Liability" on the Consolidated Balance Sheets and was adjusted to reflect fair value at each reporting date with changes in fair value reflected in the "Change in Fair Value of Convertible Debt Conversion Liability" on the Consolidated Statements of Operations. The fair value of the convertible debt conversion liability at issuance was $40,145 . On December 8, 2017, at the Company's Special Meeting of Stockholders, the Company obtained the approval from its stockholders to remove the common stock issuance restrictions in connection with conversions of the 2036 Convertible Notes. Accordingly, on December 8, 2017, the Convertible Debt Conversion Liability was remeasured at fair value at $45,933 and was then reclassified into equity. The debt liability component of 2036 Convertible Notes was determined to be $111,855 at issuance, reflecting a debt discount of $40,145 . The debt discount is to be amortized through June 2036. The effective interest rate on the debt liability component was 2.45% . In June 2016, approximately $35,101 of the net proceeds from the offering of the 2036 Convertible Notes were used to repurchase 4,060,323 shares of the Company's Common Stock in privately negotiated transactions. In addition, approximately $61,954 of the net proceeds from the offering were used to repurchase $63,912 principal amount of the Company's 2019 Convertible Notes in privately negotiated transactions. In September 2016, the Company used approximately $5,584 under the March 2016 share repurchase program to repurchase an additional $6,000 principal amount of the 2019 Convertible Notes. The repurchases resulted in a gain on debt extinguishment of $2,331 , which is reflected on the Consolidated Statements of Operations. REG Ralston In April 2017, REG Ralston, LLC ("REG Ralston") entered into a construction loan agreement ("Construction Loan Agreement") with First Midwest Bank. The Construction Loan Agreement allows REG Ralston to borrow up to $20,000 during the construction period at REG Ralston and convert it into an amortizing term debt thereafter. The loan has a maturity date of October 19, 2025. The loan requires monthly principal payments after the construction period and interest to be charged using prime rate plus 0.5% per annum. The loan agreement contains various loan covenants. At December 31, 2017, the effective interest rate on the amount borrowed under this Loan Agreement was 5.00% per annum. REG Danville In July 2017, REG Danville, LLC ("REG Danville") entered into an amended loan agreement ("Loan Agreement") with Fifth Third Bank. The Loan Agreement allows REG Danville to borrow $12,500 maturing in July 2022. The loan requires monthly principal payments and bears LIBOR-based variable interest rates. The loan agreement contains various loan covenants. At December 31, 2017, the effective interest rate on the amount borrowed under this Loan Agreement was 5.38% per annum. REG Capital In December 2017, REG Capital, LLC ("REG Capital") entered into a mortgage refinancing loan agreement ("Mortgage Refinancing Loan Agreement") with First National Bank to refinance existing mortgages on our office buildings in Ames, IA. The outstanding principal under the Mortgage Refinancing Loan Agreement is $7.4 million with a maturity date of January 3, 2028. The loan requires monthly principal payments and bears a fixed interest rate of 3.99% per annum. Lines of Credit The Company’s revolving debt at December 31 are as follows: 2017 2016 Total revolving loans (current) $ 65,525 $ 52,844 Maximum remaining available to be borrowed under revolving lines of credit $ 60,839 $ 100,237 The Company's wholly-owned subsidiaries, REG Services Group, LLC and REG Marketing & Logistics Group, LLC, are borrowers under a Credit Agreement dated December 23, 2011 with the lenders party thereto (“Lenders”) and Wells Fargo Capital Finance, LLC, as the agent, (as amended, the “M&L and Services Revolver”). The maximum commitment of the Lenders under the M&L and Services Revolver to make revolving loans is $150,000 , subject to an accordion feature, which allows the borrowers to request commitments for additional revolving loans in aggregate amount not to exceed to $50,000 , the making of which is subject to customary conditions, including the consent of Lenders providing such additional commitments. The maturity date of the M&L and Services Revolver is September 30, 2021. Loans advanced under the M&L and Services Revolver bear interest based on a one-month LIBOR rate (which shall not be less than zero ), plus a margin based on Quarterly Average Excess Availability (as defined in the Revolving Credit Agreement), which may range from 1.75% per annum to 2.25% per annum. The M&L and Services Revolver contains various loan covenants that restrict each subsidiary borrower’s ability to take certain actions, including restrictions on incurrence of indebtedness, creation of liens, mergers or consolidations, dispositions of assets, repurchase or redemption of capital stock, making certain investments, making distributions to us unless certain conditions are satisfied, entering into certain transactions with affiliates or changing the nature of the subsidiary’s business. In addition, the subsidiary borrowers are required to maintain a fixed charge coverage ratio of at least 1.0 to 1.5 if excess availability under the M&L and Services Revolver is less than 10% of the total $150,000 of current revolving loan commitments, or $15,000 currently. The M&L and Services Revolver is secured by the subsidiary borrowers’ membership interests and substantially all of their assets. In addition, the M&L and Services Revolver is secured by the accounts receivable and inventory of REG Albert Lea, LLC, REG Houston, LLC, REG New Boston, LLC, and REG Geismar, LLC (collectively, the "Plant Loan Parties") subject to a $40,000 limitation with respect to each of the Plant Loan Parties. REG Germany has a trade finance facility agreement ("Uncommitted Credit Facility Agreement") with BNP Paribas in Europe, which allows it to borrow up to $25,000 for funding the purchase of goods and services. Amounts outstanding under the Uncommitted Credit Facility Agreement bear variable interest and are payable as stipulated in the agreement. The amount that can be borrowed under the agreement can be amended, cancelled or restricted at BNP Paribas's sole discretion and therefore is not included in the maximum available to be borrowed under lines of credit above. The Uncommitted Credit Facility Agreement contains various loan covenants that require REG Germany to maintain certain financial measures. At December 31, 2017 , the nominal interest rates ranged from 1.50% to 2.00% per annum. Maturities of the term debt, including the convertible debt, are as follows for the years ending December 31: 2018 $ 13,397 2019 76,856 2020 6,824 2021 5,613 2022 3,548 Thereafter 122,322 Total term debt 228,560 Less: current portion 13,397 Total long-term debt $ 215,163

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES On December 22, 2017, President Donald Trump signed into law “H.R. 1”, formerly known as the “Tax Cuts and Jobs Act” (the “Tax Legislation”). The Tax Legislation, which was effective on January 1, 2018, significantly revises the U.S. tax code by, among other things, lowering the corporate income tax rate from 35% to 21% , limiting deductibility of interest expense, implementing a hybrid-territorial tax system imposing a repatriation tax on deemed repatriated earnings of foreign subsidiaries (the “transition tax”), and enacted additional international tax provisions, including a minimum tax on global intangible low-taxed income (“GILTI”) and a new base erosion anti-abuse tax (“BEAT”). The Company has recorded the impact of the Tax Legislation in the financial statements as a non-cash net tax benefit of $13,712 in the fourth quarter of 2017, which includes a write-down of $123,289 related to the re-measurement of U.S. deferred tax assets and $137,001 release of U.S. valuation allowances, both due to the lower enacted corporate tax rate. The non-cash tax benefit recorded is a provisional amount, and the Company continues to evaluate the impact the Tax Legislation will have on its financial condition and results of operations. Income tax benefit (expense) for the years ended December 31 is as follows: 2017 2016 2015 Current income tax benefit (expense) Federal $ — $ — $ — State (45 ) 94 — Foreign 421 (1,036 ) (225 ) 376 (942 ) (225 ) Deferred income tax benefit (expense) Federal 22,619 2,113 24,151 State 10,282 6,936 9,736 Foreign 2,674 (2,560 ) 1,035 Change in enacted tax rates (123,289 ) — — Net operating loss carryforwards created 17,466 105,165 88,110 (70,248 ) 111,654 123,032 Income tax benefit (expense) before valuation allowances (69,872 ) 110,712 122,807 Deferred tax valuation allowances 100,362 (114,980 ) (114,106 ) Income tax benefit (expense) $ 30,490 $ (4,268 ) $ 8,701 A reconciliation of the reported amount of income tax expense to the amount computed by applying the statutory federal income tax rate to earnings from continuing operations before income taxes is as follows: 2017 2016 2015 U.S. Federal income tax expense at a statutory rate of 35 percent $ 38,349 $ (17,143 ) $ 56,144 State taxes, net of federal income tax benefit 8,160 11,442 12,777 Tax position on government incentives 9,402 117,630 85,423 Change in enacted tax rates (123,289 ) — — Goodwill impairment tax impact — 2,876 (35,062 ) Bargain purchase gain — — 1,875 Foreign net operating loss expiration — (2,383 ) — Other (2,494 ) (1,710 ) 1,650 Total (expense) benefits for income taxes before valuation allowances (69,872 ) 110,712 122,807 Valuation allowances 100,362 (114,980 ) (114,106 ) Total benefit (expense) for income taxes $ 30,490 $ (4,268 ) $ 8,701 The Company receives government incentive payments and excludes this revenue from federal and state taxable income. This tax position of excluding government incentives from taxable income has been accepted by the Internal Revenue Service under audit for 2010 and 2011 and has been approved by the Joint Committee on Taxation. As a result of excluding these government incentive payments, the Company currently has cumulative losses in recent years and initially established a valuation allowance in 2013 to reduce its total deferred tax assets to the amount more-likely-than-not to be realized. In 2015, the Company had a non-cash impairment charge for goodwill of $175,028 , of which $91,961 was not deductible for tax purposes. A $32,186 tax impact related to the non-deductible portion of the goodwill impairment charge was reflected in the tax reconciliation above for 2015 in the amount of $35,062 , offset with $2,876 in 2016. The tax effects of temporary differences that give rise to the Company’s deferred tax assets and liabilities at December 31 are as follows: 2017 2016 Deferred Tax Assets: Net operating loss carryforwards $ 249,371 $ 346,768 Goodwill 26,448 42,082 Capitalized research and development 9,788 11,394 Stock-based compensation 3,924 5,853 Risk management unrealized gain (loss) 1,879 874 Tax credit carryforwards 1,597 1,597 Accrued compensation 1,062 4,419 Inventory capitalization 1,491 3,227 Other 2,945 6,623 Deferred tax assets 298,505 422,837 Deferred Tax Liabilities: Property, plant and equipment (27,314 ) (61,431 ) Convertible debt (9,889 ) (5,797 ) Intangibles (2,195 ) (3,591 ) Prepaid expenses (1,393 ) (1,724 ) Deferred revenue — (3,454 ) Other (544 ) (2,084 ) Deferred tax liabilities (41,335 ) (78,081 ) Net deferred tax assets (liabilities) 257,170 344,756 Valuation allowance (265,362 ) (365,035 ) Net deferred tax liabilities $ (8,192 ) $ (20,279 ) At December 31, 2017 , the Company has recorded a deferred tax asset before valuation allowance of $249,371 reflecting the benefit of federal, state and foreign net operating loss carry-forwards. Federal net operating loss carry-forward totals $934,137 and will begin to expire in 2028 , while the amount and expiration dates of state net operating losses vary by jurisdiction. Changes in ownership of the Company, as defined by Section 382 of the Internal Revenue Code of 1986, as amended, in any one year may limit the utilization of federal and state net operating losses and credit carry-forwards. The Company has performed an ownership change analysis in 2017 to determine the impact of changes in ownership on utilization of carry-forward attributes, the results of which have been incorporated into our financial statements. In evaluating available evidence around the recoverability of net deferred tax assets, the Company considers, among other factors, historical financial performance, expectation of future earnings, length of statutory carry-forward periods and ability to carry back losses to prior periods, experience with operating loss and tax credit carry-forwards expiring unused, tax planning strategies and timing for the of reversals of temporary differences. In evaluating losses, management considers the nature, frequency and severity of losses in light of the conditions giving rise to those losses. As a result of the above described tax position of excluding government incentive payments from taxable income, the Company currently has cumulative losses in recent years and has established a valuation allowance to reduce its total deferred tax assets to the amount more-likely-than-not to be realized. Activity regarding the valuation allowance for deferred tax assets was as follows: 2017 2016 2015 Beginning of year balance $ 365,035 $ 250,164 $ 136,547 Changes in valuation allowance charged to income 36,639 114,980 114,106 Change in enacted tax rates (137,001 ) — — Foreign currency translation 689 (109 ) (773 ) Acquisition — — 284 End of year balance $ 265,362 $ 365,035 $ 250,164 The Company analyzes filing positions in all of the federal and state jurisdictions where it is required to file income tax returns, and all open tax years in these jurisdictions to determine if it has any uncertain tax positions on any of its income tax returns. An uncertain tax position represents a tax position taken in a filed tax return, or planned to be taken in a tax return not yet filed, that has not been reflected in measuring income tax expense for financial reporting purposes. The Company does not recognize income tax benefits associated with uncertain tax positions where it is determined that it is not more-likely-than-not, based on the technical merits, that the position will be sustained upon examination. A reconciliation of the total amounts of unrecognized tax benefits at December 31 is as follows: 2017 2016 2015 Beginning of year balance $ 1,900 $ 1,900 $ 1,900 Decreases to tax positions taken during prior years (129 ) — — End of year balance $ 1,771 $ 1,900 $ 1,900 The amount of unrecognized tax benefits that would affect the effective tax rate if the tax benefits were recognized was $0 at December 31, 2017 , 2016 and 2015 . The remaining liability for unrecognized tax benefits is related to tax positions for which there is a related deferred tax asset. The Company does not believe it is reasonably possible that the amounts of unrecognized tax benefits existing as of December 31, 2017 will significantly increase or decrease over the next twelve months. Interest and penalties related to unrecognized tax benefits are recognized as a component of income tax expense. The Company has not recorded any such amounts in the periods presented. The Company is subject to tax in the U.S. and various state and foreign jurisdictions. The U.S. Internal Revenue Service has examined the Company's federal income tax returns through 2008, as well as 2010 and 2011, while the tax authorities in Germany have examined the Company's corporate income tax returns through 2014. All other years in the U.S. and Germany are subject to examination, while various state and other foreign income tax returns also remain subject to examination by taxing authorities. As a result of the enactment of the Tax Legislation, management’s judgment is that the Company provisionally no longer considers its foreign earnings of non-U.S. subsidiaries to be indefinitely reinvested. The change in judgment does not have a material impact on the Company’s consolidated financial statements. Although not considered indefinitely reinvested, the Company has not made a provision for U.S. or additional foreign withholding taxes due to provisional accumulated tax deficits outside the U.S. The Company has not recorded a deferred tax asset for the outside basis difference related to investments in its foreign subsidiaries as the investment is essentially permanent in duration.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	STOCK-BASED COMPENSATION On October 26, 2011, the stockholders approved the 2009 Stock Incentive Plan (the 2009 Plan) which authorizes up to 4,160,000 shares of Company Common Stock to be issued for the award of restricted stock, restricted stock units (RSUs), performance restricted stock units (PRSUs) and stock appreciation rights (SARs) at the discretion of the Company Board as compensation to employees, consultants of the Company and to non-employee directors. Under the 2009 Plan, an additional 2,350,000 shares, or 6,510,000 shares in total, are reserved for issuance as approved by shareholders on May 15, 2014 and May 8, 2017. The expense is measured at the grant-date fair value of the award and recognized as compensation expense on a straight-line basis over the service period, which is the vesting period. There was no cash flow impact resulting from the grants of these awards. The 2009 Plan is generally protected from anti-dilution via adjustments for any stock dividends, stock split, combination or other recapitalization. The Company recorded stock-based compensation expense of $6,909 , $5,896 and $5,161 for the years ended December 31, 2017 , 2016 and 2015 , respectively. The stock-based compensation costs were included as a component of selling, general and administrative expenses. At December 31, 2017 , there was $6,221 of unrecognized compensation expense related to unvested awards, which is expected to be recognized over a period of approximately 3.4 years . Restricted Stock Units The following table summarizes information about the Company’s Common Stock RSU’s granted, vested, exercised and forfeited: Number of Awards Weighted Average Issue Price Awards outstanding - January 1, 2015 616,394 $15.00 Issued 339,280 $9.34 Vested and restriction lapsed (295,089 ) $9.36 Forfeited (22,687 ) $10.56 Awards outstanding - December 31, 2015 637,898 $12.87 Issued 504,647 $9.07 Vested and restriction lapsed (249,356 ) $9.77 Forfeited (33,938 ) $8.15 Awards outstanding - December 31, 2016 859,251 $11.73 Issued 360,741 $11.91 Vested and restriction lapsed (204,198 ) $11.05 Forfeited (127,403 ) $10.04 Awards outstanding - December 31, 2017 888,391 $12.12 The RSUs convert into one share of common stock upon vesting. RSU’s cliff vest at the earlier of expressly provided service or performance conditions. The service period for these RSU awards, excluding those issued to the Company’s Board of Directors ( one year ) and certain executive management ( three to four years), is a three year period from the grant date. The performance conditions provide for accelerated vesting upon various conditions including a change in control or other common stock liquidity events. Performance Restricted Stock Units The following table summarizes information about the Company’s Common Stock RSU’s granted, vested, exercised and forfeited: Number of Awards Weighted Average Issue Price Awards outstanding -January 1, 2015 — $ — Issued 59,623 $ 9.40 Vested and restriction lapsed — $ — Forfeited — $ — Awards outstanding - December 31, 2015 59,623 $ 9.40 Issued 175,217 $ 9.06 Vested and restriction lapsed — $ — Forfeited — $ — Awards outstanding - December 31, 2016 234,840 $ 9.15 Issued 270,765 $ 11.79 Vested and restriction lapsed (87,622 ) $ 11.75 Forfeited (62,865 ) $ 9.48 Awards outstanding - December 31, 2017 355,118 $ 10.46 The PRSUs convert into one share of common stock upon vesting. PRSUs vest in different tranches upon meeting certain performance conditions, which are generally based on the Company's stock price performance and expressly provided service. These PRSUs are fair valued at grant date based on Monte Carlo simulations or at a percentage of the stock price at grant date. The derived service period for these PRSU awards as a result of the Monte Carlo simulation, is an approximately two year period from the grant date. The performance conditions provide for accelerated vesting upon various conditions including a change in control or other common stock liquidity events. Stock Appreciation Rights The following table summarizes information about SARs granted, forfeited, vested and exercisable: Number of SAR’s Weighted Average Exercise Price Weighted Average Contractual Term SAR's outstanding - January 1, 2015 1,809,302 $10.63 Granted 655,855 $9.47 Exercised (14,470 ) $9.21 Forfeited (54,561 ) $10.30 SAR's outstanding - December 31, 2015 2,396,126 $10.33 7.6 years Granted 176,824 $8.80 Exercised (8,003 ) $8.57 Forfeited (56,932 ) $10.75 SAR's outstanding - December 31, 2016 2,508,015 $10.22 6.7 years Granted — Exercised (700,765 ) $10.36 Forfeited (105,981 ) $9.66 SAR's outstanding - December 31, 2017 1,701,269 $10.20 5.7 years SAR's exercisable - December 31, 2017 1,247,161 $10.34 5.7 years SAR's expected to vest - December 31, 2017 863,626 $10.40 5.7 years The SARs vest 25% annually on each of the four anniversary dates following the grant date and expire after ten years . The fair value of each SAR grant is estimated using the Black-Scholes option-pricing model as set forth in the table below: 2017 2016 2015 The weighted average fair value of stock appreciation rights issued (per unit) $2.79 - $3.74 $2.79 - $3.74 $3.33 - $3.90 Dividend yield —% —% —% Weighted average risk-free interest rate 1.1% - 1.4% 1.1% - 1.4% 1.4% - 1.6% Weighted average expected volatility 40% 40% 40% Expected life in years 6.25 6.25 6.25 Stock Options At the end of December 31, 2014 and 2015, there were 87,026 options outstanding at $23.75 /share. Such options were forfeited during 2016. There were no outstanding stock options at December 31, 2017 and 2016. There was no intrinsic value of options granted, exercised or outstanding during the periods presented.

Operating Leases

Operating Leases	12 Months Ended
	Dec. 31, 2017
Leases, Operating [Abstract]
Operating Leases	OPERATING LEASES The Company leases certain land and equipment under operating leases. Total rent expense under operating leases was $20,013 , $22,487 and $19,814 for the years ended December 31, 2017 , 2016 and 2015 , respectively. For each of the next five calendar years and thereafter, future minimum lease payments under operating leases that have initial or remaining noncancelable lease terms in excess of one year are as follows: Total Payments 2018 $ 17,032 2019 14,243 2020 9,330 2021 8,900 2022 2,052 Thereafter 14,953 Total minimum payments $ 66,510 The Company's leases consist primarily of access to distribution terminals, biomass-based diesel storage facilities, railcars and vehicles. At the end of the lease term the Company, generally, has the option to (a) return the leased equipment to the lessor, (b) purchase the property at its then fair value or (c) renew its lease at the then fair rental value on a year-to-year basis or for an agreed upon term. Certain leases allow for adjustment to minimum rentals in future periods as determined by the Consumer Price Index.

Derivative Instruments

Derivative Instruments	12 Months Ended
	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	DERIVATIVE INSTRUMENTS The Company has entered into heating oil and soybean oil futures, swaps and options (commodity derivative contracts) to reduce the risk of price volatility related to anticipated purchases of feedstock raw materials and to protect gross profit margins from potentially adverse effects of price volatility on biomass-based diesel sales where prices are set at a future date. All of the Company’s derivatives are recorded at fair value on the Consolidated Balance Sheets. Unrealized gains and losses on commodity futures, swaps and options contracts used to risk-manage feedstock purchases or biomass-based diesel inventory are recognized as a component of biomass-based diesel costs of goods sold reflected in current results of operations. At December 31, 2017 , the net notional volumes of heating oil and soybean oil covered under the open commodity derivative contracts were 82.8 million gallons and 78.3 million pounds, respectively. The Company offsets the fair value amounts recognized for its commodity derivative contracts with cash collateral with the same counterparty under a master netting agreement. The net position is presented within Prepaid expenses and other assets in the Consolidated Balance Sheets, see "Note 8 – Other Assets". As of December 31, 2017 , the Company posted $8,798 of collateral associated with its commodity-based derivatives with a net liability position of $7,189 . The following tables provide details regarding the Company’s derivative financial instruments: December 31, 2017 December 31, 2016 Assets Liabilities Assets Liabilities Gross amounts of commodity derivative contracts recognized at fair value $ 812 $ 8,001 $ 1,272 $ 3,511 Cash collateral 8,799 — 9,366 — Total gross amount recognized 9,611 8,001 10,638 3,511 Gross amounts offset (8,001 ) (8,001 ) (3,511 ) (3,511 ) Net amount reported in the Consolidated Balance Sheets $ 1,610 $ — $ 7,127 $ — The following table sets forth the pre-tax gains (losses) included in the Consolidated Statements of Operations: Location of Gain (Loss) 2017 2016 2015 Commodity derivatives Cost of goods sold – Biomass-based diesel $ (23,437 ) $ (35,386 ) $ 35,983

Fair Value Measurement

Fair Value Measurement	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurement	FAIR VALUE MEASUREMENT The fair value hierarchy prioritizes the inputs used in measuring fair value as follows: • Level 1—Quoted prices for identical instruments in active markets. • Level 2—Quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active and model-derived valuations, in which all significant inputs are observable in active markets. • Level 3—Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. A summary of assets (liabilities) measured at fair value is as follows: As of December 31, 2017 Total Level 1 Level 2 Level 3 Commodity contract derivatives $ (7,189 ) $ (3,742 ) $ (3,447 ) $ — Contingent consideration for acquisitions $ (34,393 ) — — (34,393 ) $ (41,582 ) $ (3,742 ) $ (3,447 ) $ (34,393 ) As of December 31, 2016 Total Level 1 Level 2 Level 3 Commodity contract derivatives $ (2,239 ) (1,297 ) (942 ) — Convertible debt conversion liability $ (27,100 ) — (27,100 ) — Contingent consideration for acquisitions $ (46,568 ) — — (46,568 ) $ (75,907 ) $ (1,297 ) $ (28,042 ) $ (46,568 ) The following is a reconciliation of the beginning and ending balances for liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) during the years ended as follows: Contingent Consideration for Acquisitions 2017 2016 Balance at beginning of period, January 1 $ 46,568 $ 41,712 Fair value of contingent consideration at measurement date — 4,500 Change in estimates included in earnings 2,484 7,904 Settlements (14,659 ) (7,548 ) Balance at end of period, December 31 $ 34,393 $ 46,568 The Company used the following methods and assumptions to estimate fair value of its financial instruments: Commodity contract derivatives: The instruments held by the Company consist primarily of futures contracts, swap agreements, purchased put options and written call options. The fair value of contracts based on quoted prices of identical assets in an active exchange-traded market is reflected in Level 1. Contract fair value is determined based on quoted prices of similar contracts in over-the-counter markets and are reflected in Level 2. Contingent consideration for acquisitions: The fair value of the contingent consideration regarding REG Life Sciences, LLC ("REG Life Sciences") is determined using an expected present value technique. Expected cash flows are determined using the probability weighted-average of possible outcomes that would occur should achievement of certain milestones related to the development and commercialization of products from REG Life Sciences' technology occur. There is no observable market data available to use in valuing the contingent consideration; therefore, the Company developed its own assumptions related to the expected future delivery of product enhancements to estimate the fair value of these liabilities. An 8.0% discount rate is used to estimate the fair value of the expected payments. The fair value of all other contingent consideration is determined using an expected present value technique. Expected cash flows are determined using the probability weighted-average of possible outcomes that would occur should the achievement of certain milestones related to the production and/or sale of biomass-based diesel at the specific production facility. A discount rate ranging from 5.8% to 10.0% is used to estimate the fair value of the expected payments. Convertible debt conversion liability: The fair value of the convertible debt conversion liability was estimated using the Black-Scholes model incorporating the terms and conditions of the 2036 Convertible Notes and considering changes in the prices of the Company's common stock, Company stock price volatility, risk-free rates and changes in market rates. The valuations are, among other things, subject to changes in the Company's credit worthiness as well as change in general market conditions. As the majority of the assumptions used in the calculations are based on market sources, the fair value of the convertible conversion liability is reflected in Level 2. Debt and lines of credit: The fair value of long-term debt and lines of credit was established using discounted cash flow calculations and current market rates reflecting Level 2 inputs. The estimated fair values of the Company’s financial instruments, which are not recorded at fair value are as follows as of December 31: 2017 2016 Asset (Liability) Carrying Amount Estimated Fair Value Asset (Liability) Carrying Amount Estimated Fair Value Financial Liabilities: Debt and lines of credit $ (294,085 ) $ (273,983 ) $ (270,735 ) $ (264,267 )

Net Income (Loss) Per Share

Net Income (Loss) Per Share	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Net Income (Loss) Per Share	NET INCOME (LOSS) PER SHARE Basic net income per common share is presented in conformity with the two-class method required for participating securities. Participating securities include, or have included, Series A Preferred Stock, Series B Preferred Stock and RSU's. Under the two-class method, net income is reduced for distributed and undistributed dividends earned in the current period. The remaining earnings are then allocated to Common Stock and the participating securities. The Company calculates the effects of participating securities on diluted earnings per share (EPS) using both the “if-converted or treasury stock” and "two-class" methods and discloses the method which results in a more dilutive effect. The effects of Common Stock options, warrants, stock appreciation rights and convertible notes on diluted EPS are calculated using the treasury stock method unless the effects are anti-dilutive to EPS. The following potentially dilutive average number of securities were excluded from the calculation of diluted net income per share attributable to common stockholders during the periods presented as the effect was anti-dilutive: Year Ended December 31, 2017 2016 2015 Options to purchase common stock — 43,513 87,026 Stock appreciation rights 622,633 2,422,716 2,072,130 2019 Convertible notes 5,567,112 7,895,675 10,838,218 2036 Convertible notes 14,106,725 8,209,651 — Total 20,296,470 18,571,555 12,997,374 The following table presents the calculation of diluted net income per share for the years ended December 31, 2017 , 2016 and 2015 (in thousands, except share and per share data): 2017 2016 2015 Net income (loss) attributable to the Company's common stockholders - Basic $ (79,079 ) $ 43,453 $ (151,392 ) Plus (less): effect of participating securities — 874 — Net income (loss) attributable to common stockholders (79,079 ) 44,327 (151,392 ) Less: effect of participating securities — (874 ) — Net income (loss) attributable to the Company's common stockholders - Diluted $ (79,079 ) $ 43,453 $ (151,392 ) Shares: Weighted-average shares outstanding - Basic 38,731,015 40,897,549 43,958,803 Adjustment to reflect stock appreciation right conversions — 5,311 — Weighted-average shares outstanding - Diluted 38,731,015 40,902,860 43,958,803 Net income (loss) per share attributable to common stockholders - Diluted $ (2.04 ) $ 1.06 $ (3.44 )

Reportable Segments and Geograp

Reportable Segments and Geographic Information	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Reportable Segments and Geographic Information	REPORTABLE SEGMENTS AND GEOGRAPHIC INFORMATION The Company reports its reportable segments based on products and services provided to customers. The Company re-assesses its reportable segment on an annual basis. During the fourth quarter of 2015, the Company determined that as activities surrounding its renewable chemicals business increase, it changed the composition of its operating segments from two reportable segments to three reportable segments by presenting Renewable Chemicals separate from Biomass-based diesel. The new reportable segments generally align the Company's external financial reporting segments with its new internal operating segments, which are based on its internal organizational structure, operating decisions and performance assessment. There are no changes to the Company's assessments in 2017 and 2016. As such, the Company's reportable segments at December 31, 2017 include Biomass-based diesel, Services, Renewable Chemicals and Corporate and other activities. The accounting policies of the segments are the same as those described in the summary of significant accounting policies. All prior period disclosures below have been recast to present results on a comparable basis. The Biomass-based diesel segment processes waste vegetable oils, animal fats, virgin vegetable oils and other feedstocks and methanol into biomass-based diesel. The Biomass-based diesel segment also includes the Company’s purchases and resale of biomass-based diesel produced by third parties. Revenue is derived from the purchases and sales of biomass-based diesel, RINs and raw material feedstocks acquired from third parties, sales of biomass-based diesel produced under toll manufacturing arrangements with third party facilities, sales of processed biomass-based diesel from Company facilities, related by-products and renewable energy government incentive payments, in the U.S. and internationally. The Services segment offers services for managing the construction of biomass-based diesel production facilities and managing ongoing operations of third party plants and collects fees related to the services provided. The Company does not allocate items that are of a non-operating nature or corporate expenses to the business segments. Revenues are recorded by the Services segment at cost. The Renewable Chemicals segment consists of research and development activities involving the production of renewable chemicals, additional advanced biofuels and other products from the Company's proprietary microbial fermentation process and the operations of a demonstration scale facility located in Okeechobee, Florida. The Renewable Chemicals segment started to have research and development collaborative and initial product revenues in 2016. The Corporate and Other segment includes trading activities related to petroleum-based heating oil and diesel fuel as well as corporate activities, which consist of corporate office expenses such as compensation, benefits, occupancy and other administrative costs, including management service expenses. Corporate and other also includes income/(expense) not associated with the reportable segments, such as corporate general and administrative expenses, shared service expenses, interest expense and interest income, all reflected on an accrual basis of accounting. In addition, corporate and other includes cash and other assets not associated with the reportable segments, including investments. Intersegment revenues are reported by the Services and Corporate and Other segments. The following table represents the significant items by reportable segment for the results of operations for the years ended December 31, 2017 , 2016 and 2015 : 2017 2016 2015 Net sales: Biomass-based Diesel (includes REG Germany's net sales of $171,175, $171,358, and $145,039, respectively) $ 2,039,982 $ 1,952,361 $ 1,326,452 Services 103,215 87,014 102,731 Renewable Chemicals 4,531 2,065 — Corporate and other 212,557 106,572 68,984 Intersegment revenues (202,042 ) (106,780 ) (110,823 ) $ 2,158,243 $ 2,041,232 $ 1,387,344 Income (loss) before income taxes Biomass-based diesel (includes REG Germany's income (loss) of ($7,544), $5,007, and $(1,643), respectively) $ (63,925 ) $ 64,814 $ (100,152 ) Services 2,899 2,970 6,323 Renewable Chemicals (19,326 ) (19,787 ) (52,728 ) Corporate and other (29,217 ) 984 (13,854 ) $ (109,569 ) $ 48,981 $ (160,411 ) Depreciation and amortization expense, net: Biomass-based diesel (includes REG Germany's amounts of $2,990, $2,849, and $3,259, respectively) $ 31,011 $ 29,018 $ 22,799 Services 1,092 613 302 Renewable Chemicals 2,666 1,550 1,413 Corporate and other 2,167 1,696 1,362 $ 36,936 $ 32,877 $ 25,876 Cash paid for purchases of property, plant and equipment: Biomass-based diesel (includes REG Germany's amounts of $3,241, $1,353, and $1,816, respectively) $ 60,734 $ 52,952 $ 59,859 Services 3,826 4,731 1,510 Renewable Chemicals 14 473 672 Corporate and other 2,998 2,549 2,436 $ 67,572 $ 60,705 $ 64,477 2017 2016 Goodwill: Biomass-based diesel $ — $ — Services 16,080 16,080 Renewable Chemicals — — $ 16,080 $ 16,080 Assets: Biomass-based diesel (including REG Germany's assets of $55,761 and $51,822) $ 898,180 $ 1,026,349 Services 55,581 53,823 Renewable Chemicals 21,168 22,883 Corporate and other 386,590 299,825 Intersegment eliminations (355,923 ) (266,277 ) $ 1,005,596 $ 1,136,603 Geographic Information: The following geographic data include net sales attributed to the countries based on the location of the subsidiaries making the sale and long-lived assets based on physical location. Long-lived assets represent the net book value of property, plant and equipment. 2017 2016 2015 Net sales: United States $ 1,961,303 $ 1,869,874 $ 1,242,305 Germany 171,175 171,358 — 145,039 Other Foreign 25,765 — — Total Foreign 196,940 171,358 145,039 $ 2,158,243 $ 2,041,232 $ 1,387,344 2017 2016 Long-lived assets: United States 566,028 580,868 Germany 20,689 18,472 Other Foreign 680 134 Total Foreign 21,369 18,606 587,397 599,474

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES The Company is involved in legal proceedings in the normal course of business. The Company currently believes that any ultimate liability arising out of such proceedings will not have a material adverse effect on the Company’s financial position, results of operations or cash flows. The Company has entered into contracts for supplies of hydrogen, nitrogen and utilities for the REG Geismar production facility and natural gas for REG Albert Lea. The following table outlines the minimum take or pay requirement related to the purchase of hydrogen, nitrogen, utilities and natural gas. 2018 $ 3,784 2019 3,748 2020 3,297 2021 2,976 2022 2,976 Thereafter 6,798 Total $ 23,579 As of December 31, 2017 , REG Geismar relies on one supplier to provide hydrogen necessary to execute the production process. Any disruptions to the hydrogen supply during production from this supplier will result in the shutdown of the REG Geismar plant operations. The Company is currently seeking additional hydrogen suppliers for the REG Geismar facility.

Subsequent Events (Notes)

Subsequent Events (Notes)	12 Months Ended
	Dec. 31, 2017
Subsequent Events [Abstract]
Subsequent Events [Text Block]	SUBSEQUENT EVENTS On February 9, 2018, President Trump signed into law the H.R.1892, which reinstated a set of tax extender items including the retroactive reinstatement of the federal biodiesel blenders tax credit for 2017. The retroactive credit for 2017 is estimated to result in a net benefit to the Company of approximately $210 million to $220 million in the first half of 2018. The net benefit received will increase the Company’s income before income taxes by a similar amount. The Company will recognize the federal biodiesel blenders tax credit during the first quarter of 2018.

Supplemental Quarterly Informat

Supplemental Quarterly Information (Unaudited)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Supplemental Quarterly Information (Unaudited)	SUPPLEMENTAL QUARTERLY INFORMATION (UNAUDITED) The following table represents the significant items for the results of operations on a quarterly basis for the years ended December 31, 2017 and 2016 : Three Months Three Months Three Months Three Months Revenues $ 418,893 $ 535,103 $ 626,983 $ 577,264 Gross profit (loss) 17,283 31,454 14,795 20,049 Selling, general, and administrative expenses including research and development expense 26,505 25,993 29,639 25,379 Impairment of property, plant and equipment — 1,341 — 48,532 Net income (loss) from operations (9,222 ) 4,120 (14,844 ) (53,862 ) Other income (expense), net (5,617 ) (36,969 ) 3,356 3,469 Net income (loss) attributable to the Company (15,914 ) (34,809 ) (11,373 ) (16,983 ) Net income (loss) per share attributable to common stockholders - basic (0.41 ) (0.90 ) (0.29 ) (0.44 ) Net income (loss) per share attributable to common stockholders - diluted (0.41 ) (0.90 ) (0.29 ) (0.44 ) Three Months Three Months Three Months Three Months Revenues $ 297,870 $ 558,301 $ 624,640 $ 560,421 Gross profit (loss) 17,384 24,862 47,350 81,920 Selling, general, and administrative expenses including research and development expense 23,703 25,277 25,604 31,864 Impairment of property, plant and equipment — — — 17,893 Net income (loss) from operations (6,319 ) (415 ) 21,746 32,163 Other income (expense), net 159 7,432 558 (6,343 ) Net income (loss) attributable to the Company (6,918 ) 7,606 23,442 20,197 Net income (loss) per share attributable to common stockholders - basic (0.16 ) 0.18 0.59 0.51 Net income (loss) per share attributable to common stockholders - diluted (0.14 ) 0.18 0.59 0.51 The results of operations for the three months ended December 31, 2017 reflect an asset impairment of $44,649 (before tax) related to the Company's New Orleans facility as further described in Note 2 and the impact of the “H.R. 1”, formerly known as the “Tax Cuts and Jobs Act” as signed into law on December 22, 2017. Refer to Note 11 for more details. The results of operations for the three months ended December 31, 2016 reflected an asset impairment of $15,593 (before tax) related to the Company's Emporia facility. In addition, the results of operations for the three months ended September 30, 2017 and December 31, 2017 also reflect insurance proceeds of $3,000 and $5,000 , respectively, and resulting gain on involuntary conversion of $942 and $4,387 , respectively, related to the insurance coverage on property loss due to the June 2017 incident at the Company's Madison facility. For the year ended December 31, 2016, the Company recorded in its results of operations insurance proceeds of $19,037 for the property damages related to the events at its Geismar facility, which resulted in a total gain on involuntary conversion of $8,010 .

Summary of Significant Accoun30

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Basis of Consolidation	Basis of Consolidation The consolidated financial statements include the accounts of the Company, its wholly-owned subsidiaries, and entities which it controls. All intercompany balances and transactions have been eliminated for consolidated reporting purposes.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents consists of money market funds and demand deposits with financial institutions. The Company considers all highly liquid debt instruments purchased with an original maturity of three months or less to be cash equivalents.
Accounts Receivable	Accounts Receivable Accounts receivable are carried at invoiced amount less allowance for doubtful accounts. Management estimates the allowance for doubtful accounts based on existing economic conditions, the financial conditions of customers and the amount and age of past due accounts. Receivables are considered past due if full payment is not received by the contractual due date. Past due accounts are generally written off against the allowance for doubtful accounts only after reasonable collection attempts have been exhausted.
Inventories	Inventories Inventories are valued at the lower of cost or net realizable value. Cost is determined based on the first-in, first-out method.
Renewable Identification Numbers (RINs)	Renewable Identification Numbers (RINs) When the Company produces and sells a gallon of biomass-based diesel, 1.5 to 1.7 RINs per gallon are generated. RINs are used to track compliance with Renewable Fuel Standards (RFS2). RFS2 allows the Company to attach between zero and 2.5 RINs to any gallon of biomass-based diesel. As a result, a portion of the selling price for a gallon of biomass-based diesel is generally attributable to RFS2 compliance. However, RINs that the Company generates are a form of government incentive and not a result of the physical attributes of the biomass-based diesel production. Therefore, no cost is allocated to the RIN when it is generated, regardless of whether the RIN is transferred with the biomass-based diesel produced or held by the Company pending attachment to other biomass-based diesel production sales. In addition, the Company also obtains RINs from third parties who have separated the RINs from gallons of biomass-based diesel. From time to time, the Company holds varying amounts of these separated RINs for resale. RINs obtained from third parties are initially recorded at their cost and are subsequently revalued at the lower of cost or market as of the last day of each accounting period and the resulting adjustments are reflected in costs of goods sold for the period. The value of these RINs is reflected in “Prepaid expenses and other assets” on the consolidated balance sheet. The cost of goods sold related to the sale of these RINs is determined using the average cost method, while market prices are determined by RIN values, as reported by the Oil Price Information Service (OPIS).
California's Low Carbon Fuel Standard	California’s Low Carbon Fuel Standard The Company generates Low Carbon fuel Standard (LCFS) credits for its low carbon fuels or blendstocks when its qualified low carbon fuels are imported by REG to California though approved physical pathways. LCFS credits are used to track compliance with California’s LCFS, which enables the Company to generate LCFS credits based upon the carbon intensity of qualified fuels that are imported by REG into California. Other companies can take title outside of California and generate LCFS credits instead of REG upon import into the state. One LCFS credit equates to one metric ton reduction of carbon dioxide compared to the petroleum fuel baseline so the amount of gallons of low carbon fuel consumption to generate one credit will vary. As a result, a portion of the selling price for a gallon of biomass-based diesel sold into California is also attributable to LCFS compliance. However, LCFS credits that the Company generates are a form of government incentive and not a result of the physical attributes of the biomass-based diesel production. Therefore, no cost is allocated to the LCFS credit when it is generated, regardless of whether the LCFS credit is transferred with the biomass-based diesel produced or held by the Company on other biomass-based diesel sales that do not transfer credits. In addition, the Company also obtains LCFS credits from third party trading activities. From time to time, the Company holds varying amounts of these third party LCFS credits for resale. LCFS credits obtained from third parties is initially recorded at their cost and are subsequently revalued at the lower of cost or net realizable value as of the last day of each accounting period and the resulting adjustments are reflected in costs of goods sold for the period. The value of LCFS obtained from third parties is reflected in “Prepaid expenses and other assets” on the consolidated balance sheet. The cost of goods sold related to the sale of these LCFS credits is determined using the average cost method, while market prices are determined by LCFS values, as reported by the Oil Price Information Service (OPIS). At December 31, 2017 and 2016, the Company held no LCFS credits purchased from third parties. The Company records assets acquired and liabilities assumed through the exchange of non-monetary assets based on the fair value of the assets and liabilities acquired or the fair value of the consideration exchanged, whichever is more readily determinable.
Derivative Instruments	Derivative Instruments Derivatives are recorded on the balance sheet at fair value with changes in fair value recognized in current period earnings
Property, Plant and Equipment	Property, Plant and Equipment Property, plant and equipment is recorded at cost less accumulated depreciation. Maintenance and repairs are expensed as incurred. Depreciation expense is computed on a straight-line method based upon estimated useful lives of the assets.
Goodwill	Goodwill Goodwill is tested for impairment annually on July 31 or when impairment indicators exist. Goodwill is allocated and tested for impairment by reporting units. At December 31, 2017 and 2016, the Company had goodwill in the Services reporting unit. The annual impairment test at July 31, 2017 determined that the fair value of the Services reporting unit exceeded its carrying value by approximately 49% .
Impairment of Long-lived Assets	Impairment of Long-lived Assets The Company tests its long-lived assets for recoverability when events or circumstances indicate that its carrying amount may not be recoverable. Significant assumptions used in the undiscounted cash flow analysis, when it is required, include the projected demand for biomass-based diesel based on annual renewable fuel volume obligations under the Renewable Fuel Standards (RFS2), the Company's capacity to meet that demand, the market price of biomass-based diesel and the cost of feedstock used in the manufacturing process. For facilities under construction, estimates also include the capital expenditures necessary to complete construction of the plant and the projected costs of financing.
Convertible Debt and Capped Call Transaction	Convertible Debt In June 2016, the Company issued $152,000 aggregate principal amount of 4% convertible senior notes due 2036 (the "2036 Convertible Notes"). The Company could not elect to issue shares of common stock upon conversion of the 2036 Convertible Notes to the extent such election would result in the issuance of more than 19.99% of the common stock outstanding immediately before the issuance of the 2036 Convertible Notes until the Company received stockholder approval for such issuance. As a result, the embedded conversion option was accounted for as an embedded derivative liability. On December 8, 2017, at the special meeting of stockholders, the Company obtained the approval from its stockholders to remove the common stock issuance restrictions in connection with conversions of the 2036 Convertible Notes. Accordingly, the embedded conversion option after being fair valued at $45,933 and net of tax of $18,025 , has been reclassified into Additional Paid-in Capital at December 8, 2017. Fair value adjustments related to this liability of $18,833 were recorded for the year ended December 31, 2017 . See "Note 10 - Debt" for a further description of the transaction. Capped Call Transaction In connection with the issuance of the 2014 convertible senior notes, the Company entered into capped call transactions. The purchased capped call transactions were recorded as a reduction to common stock-additional paid-in-capital. Because this was considered to be an equity transaction and qualifies for the derivative scope exception, no future changes in the fair value of the capped call will be recorded by the Company. During 2016, in connection with the issuance of the 2036 Convertible Notes, certain call options covered by the original capped call transaction were rebalanced and reset to cover 100% of the total number of shares of the Company's Common Stock underlying the remaining principal of the 2019 Convertible Notes. The impact of these transactions, net of tax, was reflected as an addition/reduction to common stock-additional paid-in capital as presented in the Consolidated Statements of Stockholders' Equity.
Security Repurchase Programs	Security Repurchase Programs In December 2017, the Company's board of directors approved a repurchase program of up to $75,000 of the Company's convertible notes and/or shares of common stock. Under the program, the Company may repurchase convertible notes or shares from time to time in open market transactions, privately negotiated transactions or by other means. The timing and amount of repurchase transactions were determined by the Company's management based on its evaluation of market conditions, share price, bond price, legal requirements and other factors.
Foreign Currency Transactions and Translations	Foreign Currency Transactions and Translation The Company’s reporting and functional currency is U.S. dollars. Monetary assets and liabilities denominated in currencies other than U.S. dollars are remeasured into their respective functional currencies at exchange rates in effect at the balance sheet date. The resulting exchange gain or loss is included in the Company’s Consolidated Statements of Operations as foreign exchange gain (loss) unless the remeasurement gain or loss relates to an intercompany transaction that is of a long-term investment nature and for which settlement is not planned or anticipated in the foreseeable future. Gains or losses arising from translation of such transactions are reported as a component of accumulated other comprehensive income (loss) in the Company’s Consolidated Balance Sheets. The Company translates the assets and liabilities of its foreign subsidiaries from their respective functional currencies to U.S. dollars at the appropriate spot rates as of the balance sheet date. Generally, the Company's foreign subsidiaries use the local currency as their functional currency. Changes in the carrying value of these assets and liabilities attributable to fluctuations in spot rates are recognized in foreign currency translation adjustment, a component of accumulated other comprehensive income (loss) in the Company’s Consolidated Balance Sheets. The other comprehensive loss amounts presented in the Company's Consolidated Statements of Comprehensive Income (Loss) and Consolidated Statements of Stockholders' Equity mainly include the foreign currency translation adjustment resulting from translating the financial statements of certain subsidiaries from Euros to US Dollars, the Company's functional currency.
Revenue Recognition	Revenue Recognition The Company recognizes revenues from the following sources: • the sale of biomass-based diesel and its co-products, as well as Renewable Identification Numbers (RINs), California Low Carbon Fuel Standard credits (LCFS credits) and raw material feedstocks, purchased or produced by the Company at owned manufacturing facilities and manufacturing facilities with which the Company has tolling arrangements; • the resale of biomass-based diesel, RINs, LCFS credits and raw material feedstocks acquired from third parties; • the sale of petroleum-based heating oil and diesel fuel acquired from third parties, along with the sale of these items further blended with biodiesel produced at wholly owned facilities; • incentives received from federal and state programs for renewable fuels; and • fees received for the marketing and sales of biomass-based diesel produced by third parties and from managing operations of third party facilities. Biomass-based diesel, including RINs and LCFS credits, and raw material feedstock revenues are recognized where there is persuasive evidence of an arrangement, delivery has occurred, the price has been fixed or is determinable and collectability can be reasonably assured. Fees received under toll manufacturing agreements with third parties are generally established as an agreed upon amount per gallon of biomass-based diesel produced. The fees are recognized where there is persuasive evidence of an arrangement, delivery has occurred, the price has been fixed or is determinable and collectability can be reasonably assured. Revenues associated with the governmental incentive programs are recognized when the amount to be received is determinable, collectability is reasonably assured and the sale of product giving rise to the incentive has been recognized. The Company received funds from the United States Department of Agriculture (USDA) in the amount of $607 , $434 and $624 for the years ended December 31, 2017 , 2016 and 2015 , respectively. The Company records amounts when it has received notification of a payment from the USDA or is in receipt of the funds and records the awards under the Program in "Biomass-based diesel government incentives" as they are closely associated with the Company's biomass-based diesel production activities.
Freight	Freight Amounts billed to customers for freight are included in biomass-based diesel sales. Costs incurred for freight are included in costs of goods sold.
Advertising Costs	Advertising Costs Advertising costs are charged to expense as they are incurred.
Research and Development	Research and Development Research and development (R&D) costs are charged to expense as incurred. In process research and development (IPR&D) assets acquired in connection with acquisitions are recorded on the Consolidated Balance Sheets as intangible assets.
Employee Benefits Plan	Employee Benefits Plan The Company sponsors an employee savings plan under Section 401(k) of the Internal Revenue Code. The Company makes matching contributions equal to 50% of the participant’s pre-tax contribution up to a maximum of 6% of the participant’s eligible earnings.
Stock-Based Compensation	Stock-Based Compensation Stock-based compensation expense is measured at the grant-date fair value of the award and recognized as compensation expense over the vesting period.
Income Taxes	Income Taxes The Company’s income tax provision, deferred income tax assets and liabilities, and liabilities for uncertain tax benefits represent the company’s best estimate of current and future income taxes to be paid. The annual tax rate is based on income tax laws, statutory tax rates, taxable income levels and tax planning opportunities available in various jurisdictions where the company operates. These tax laws are complex and require significant judgment to determine the consolidated provision for income taxes. Changes in tax laws, statutory tax rates and estimates of the company’s future taxable income levels could result in actual realization of deferred taxes being materially different from amounts provided for in the consolidated financial statements. The indefinite reinvestment in the earnings of non-US subsidiaries assertion is determined by management’s judgment about and intentions concerning future investment in operations
Concentrations	Concentrations One customer represented slightly less than 10% of the total consolidated revenues of the Company for the years ended December 31, 2017 , 2016 and 2015 . All customer amounts disclosed in the table are related to biomass-based diesel sales: 2017 2016 2015 Customer A $ 182,236 $ 144,849 $ 114,030 The Company maintains cash balances at financial institutions, which may at times exceed the $250 coverage by the U.S. Federal Deposit Insurance Company.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the dates of the financial statements and reported amounts of revenues and expenses during the reporting periods. These estimates are based on information that is currently available to management and on various assumptions that the Company believes to be reasonable under the circumstances. Actual results could differ from those estimates.
New Accounting Pronouncements	New Accounting Pronouncements On February 25, 2016, the FASB issued ASU 2016-02, which introduces a lessee model that brings most leases on the balance sheet. The new standard also aligns many of the underlying principles of the new lessor model with those in ASC 606, the FASB’s new revenue recognition standard (e.g., those related to evaluating when profit can be recognized). Furthermore, the ASU addresses other concerns related to the current leases model. The ASU is effective for annual periods beginning after December 15, 2018 and interim periods therein. The Company has started the process to compile and review all of its leases. While the Company is continuing to assess all potential impacts of the standard, the Company currently believes the most significant impact relates to the classifications of its accounting for office, railcar and terminal operating leases. The Company plans to apply a modified retrospective transition approach to each applicable lease that exists at January 1, 2017 as well as leases entered after this date. In March 2016, the FASB issued ASU 2016-08, "Revenue from Contracts with Customers (Topic 606): Principal versus Agent Consideration (Reporting Revenue Gross versus Net)" which clarifies how an entity should identify the unit of accounting for the principal versus agent evaluation and how it should apply the control principle to certain types of arrangements, such as service transactions. The guidance also re-frames the indicators to focus on evidence that an entity is acting as a principal rather than an agent. The guidance is effective for public business entities for fiscal years beginning after December 15, 2017 and interim periods within those fiscal years. The Company has evaluated the impact of this guidance and does not expect it to have any material impact on its consolidated financial statements. In May 2016, the FASB issued ASU 2016-12, which amends certain aspects of the new revenue standard, ASU 2014-09. The amendments address issues such as collectability; presentation of sales tax and other similar taxes collected from customers; noncash consideration; contract modifications and completed contracts at transition; and transition technical correction. The guidance is effective for public business entities for fiscal years beginning after December 15, 2017 and interim periods within those fiscal years. The Company has evaluated the impact of this guidance and does not expect it to have any material impact on its consolidated financial statements. Effective January 1, 2018, the Company will be required to adopt the new guidance of ASC Topic 606, Revenue from Contracts with Customers (Topic 606), which will supersede the revenue recognition requirements in ASC Topic 605, Revenue Recognition. Topic 606 requires the Company to recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The new guidance requires us to apply the following steps: (1) identify the contract with a customer; (2) identify the performance obligations in the contract; (3) determine the transaction price; (4) allocate the transaction price to the performance obligations in the contract; and (5) recognize revenue when, or as, the Company satisfies a performance obligation. The Company has substantially completed our impact assessment and determined that the majority of its contracts will continue to be recognized at a point in time and that the number of performance obligations and the accounting for variable consideration are not expected to be significantly different from current practice. Additionally, the Company will adopt Topic 606 on a modified retrospective basis, which is not expected to result in any material cumulative effect adjustments to retained earnings and provide additional disclosures of the amount by which each financial statement line item is affected in the current reporting period, as compared to the guidance that was in effect before the change, and an explanation of the reasons for significant changes. The adoption of this new guidance will require expanded disclosures in its consolidated financial statements. On June 16, 2016, the FASB issued ASU 2016-13, which amends the Board’s guidance on the impairment of financial instruments. The ASU adds to U.S. GAAP an impairment model (known as the current expected credit loss (CECL) model) that is based on expected losses rather than incurred losses. Under the new guidance, an entity recognizes as an allowance its estimate of expected credit losses. For public companies, the ASU is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. The Company is evaluating the impact of this guidance, but does not expect it to have any material impact on its consolidated financial statements. The FASB issued ASU 2016-18 on November 17, 2016 to add or clarify guidance on the classification and presentation of restricted cash in the statement of cash flows. For public companies , the guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The Company has evaluated the impact of this guidance and determined that it will not have any material impact on its consolidated financial statements. On August 28, 2017, the FASB issued ASU 2017-12, which amends the hedge accounting recognition and presentation requirements in ASC 815. The ASU was issued to improve the transparency and understandability of information conveyed to financial statement users about an entity’s risk management activities by better aligning the entity’s financial reporting for hedging relationships with those risk management activities and reduce the complexity of and simplify the application of hedge accounting by preparers. the ASU is effective for public companies for fiscal years beginning after December 15, 2018, and interim periods therein. The Company is evaluating the impact of this ASU on its consolidated financial statements.

Summary of Significant Accoun31

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Activity regarding the allowance for doubtful accounts	Activity regarding the allowance for doubtful accounts was as follows: Balance, January 1, 2015 $ 2,273 Amount charged to selling, general and administrative expenses (803 ) Charge-offs, net of recoveries (119 ) Balance, December 31, 2015 1,351 Amount charged to selling, general and administrative expenses 630 Charge-offs, net of recoveries (106 ) Balance, December 31, 2016 1,875 Amount charged to selling, general and administrative expenses 139 Charge-offs, net of recoveries (779 ) Balance, December 31, 2017 $ 1,235
Estimated useful lives	Depreciation expense is computed on a straight-line method based upon estimated useful lives of the assets. Estimated useful lives are as follows: Automobiles and trucks 5 years Computers and office equipment 5 years Office furniture and fixtures 7 years Machinery and equipment 5-30 years Leasehold improvements the lesser of the lease term or 30 years Buildings and improvements 30-40 years
Concentration risk by customer	One customer represented slightly less than 10% of the total consolidated revenues of the Company for the years ended December 31, 2017 , 2016 and 2015 . All customer amounts disclosed in the table are related to biomass-based diesel sales: 2017 2016 2015 Customer A $ 182,236 $ 144,849 $ 114,030

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2017
Sanimax
Business Acquisition [Line Items]
Schedule of Business Acquisitions	The following table summarizes the consideration paid for the acquisition from Sanimax Energy: March 15, 2016 Consideration at fair value for acquisition from Sanimax: Cash $ 12,541 Common stock 4,050 Contingent consideration 4,500 Total $ 21,091 The following table summarizes the fair values of the assets acquired at the acquisition date. March 15, 2016 Assets (liabilities) acquired from Sanimax Energy: Inventory $ 1,591 Property, plant and equipment 19,500 Total identifiable assets acquired 21,091 Accrued expenses and liabilities — Net identifiable assets acquired $ 21,091
Acquisition, Pro Forma	The following unaudited pro forma condensed combined results of operations assume that the Sanimax Energy acquisition was completed as of January 1, 2015 and as if the stock had been issued on the same date. Year ended December 31, 2017 Year ended December 31, 2016 Year ended December 31, 2015 Revenues $ 2,158,243 $ 2,049,658 $ 1,406,580 Net income (loss) attributable to the Company's common stockholders (79,079 ) 43,453 (157,524 ) Basic net income (loss) per share attributable to common stockholders $(2.04) $1.06 $(3.50)
Imperium Renewables, Inc.
Business Acquisition [Line Items]
Schedule of Business Acquisitions	The following table summarizes the estimated fair values of the assets acquired and liabilities assumed at the acquisition date. August 19, 2015 Assets (liabilities) acquired of Imperium: Cash $ 168 Accounts receivable 8,274 Inventory 18,989 Other current assets 87 Property, plant and equipment 46,476 Intangible assets 2,900 Total identifiable assets acquired 76,894 Accounts payable (4,828 ) Accrued expenses and other liabilities (942 ) Debt (5,225 ) Deferred tax liabilities (3,483 ) Total liabilities assumed (14,478 ) Net identifiable assets acquired 62,416 Less: Bargain purchase gain 5,358 Net assets acquired $ 57,058 The following table summarizes the consideration paid for Imperium: August 19, 2015 Consideration at fair value for Imperium: Cash $ 36,748 Common stock 15,310 Contingent consideration 5,000 Total $ 57,058

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2017
Inventory Disclosure [Abstract]
Inventories	Inventories consist of the following at December 31: 2017 2016 Raw materials $ 39,975 $ 34,560 Work in process 3,523 3,775 Finished goods 92,049 107,073 Total $ 135,547 $ 145,408

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Property, plant and equipment	Company's owned property, plant and equipment consists of the following at December 31: 2017 2016 Land $ 10,480 $ 5,412 Building and improvements 140,261 134,398 Leasehold improvements 10,806 10,520 Machinery and equipment 534,991 511,461 696,538 661,791 Accumulated depreciation (175,531 ) (138,372 ) 521,007 523,419 Construction in process 66,390 76,055 Total $ 587,397 $ 599,474

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Components of Intangible assets	Amortizing intangible assets consist of the following at December 31: December 31, 2017 Cost Accumulated Amortization Net Weighted Average Remaining Life Raw material supply agreement $ 6,230 $ (2,408 ) $ 3,822 8.0 years Renewable diesel technology 8,300 (1,983 ) 6,317 11.5 years Acquired customer relationships 2,900 (686 ) 2,214 7.6 years Ground lease 200 (141 ) 59 3.9 years In-process research and development 15,956 (1,241 ) 14,715 13.8 years Total intangible assets $ 33,586 $ (6,459 ) $ 27,127 December 31, 2016 Cost Accumulated Amortization Net Weighted Average Remaining Life Raw material supply agreement $ 6,230 $ (1,987 ) $ 4,243 9.0 years Renewable diesel technology 8,300 (1,429 ) 6,871 12.5 years Acquired customer relationships 2,900 (396 ) 2,504 8.6 years Ground lease 200 (127 ) 73 4.9 years In-process research and development 15,956 (177 ) 15,779 14.8 years Total intangible assets $ 33,586 $ (4,116 ) $ 29,470
Estimated amortization expense	Estimated amortization expense for fiscal years ended December 31 is as follows: 2018 $ 2,425 2019 2,433 2020 2,440 2021 2,447 2022 2,441 Thereafter 14,941 Total $ 27,127

Other Assets (Tables)

Other Assets (Tables)	12 Months Ended
	Dec. 31, 2017
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Summary of prepaid expense and other current assets	Prepaid expenses and other current assets consist of the following at December 31: 2017 2016 Commodity derivatives and related collateral, net $ 1,610 $ 7,127 Prepaid expenses 11,733 10,665 Deposits 2,899 2,897 RIN inventory 27,028 9,398 Taxes receivable 6,356 4,539 Other 2,254 1,646 Total $ 51,880 $ 36,272
Summary of other noncurrent assets	Other noncurrent assets consist of the following at December 31: 2017 2016 Spare parts inventory $ 2,764 $ 3,532 Catalysts 2,962 4,479 Deposits 381 2,392 Other 933 2,227 Total $ 7,040 $ 12,630

Accrued Expenses and Other Li37

Accrued Expenses and Other Liabilities (Tables)	12 Months Ended
	Dec. 31, 2017
Accrued Liabilities [Abstract]
Summary of accrued expenses and other liabilities	Accrued expenses and other liabilities consist of the following at December 31: 2017 2016 Accrued property taxes $ 1,353 $ 1,518 Accrued employee compensation 8,172 15,005 Accrued interest 590 537 Contingent consideration, current portion 25,545 17,637 Unfavorable lease obligation, current portion 1,129 1,828 Excise tax payable 1,046 1,603 Income tax payable 455 — Other 897 788 Total $ 39,187 $ 38,916
Summary of other noncurrent liabilities	Other noncurrent liabilities consist of the following at December 31: 2017 2016 Severance payable $ 603 $ — Straight-line lease liability 1,801 2,421 Asset retirement obligations 593 1,140 Other 1,117 1,295 Total $ 4,114 $ 4,856

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Company's borrowings	The Company’s term debt at December 31 is as follows: 2017 2016 4.00% Convertible Senior Notes, $152,000 face amount, due in June 2036 $ 116,255 $ 113,446 2.75% Convertible Senior Notes, $73,838 face amount, due in June 2019 69,859 67,254 REG Danville term loan, secured, variable interest rate of LIBOR plus 4%, due in July 2022 11,460 8,163 REG Newton term loan, secured, variable interest rate of LIBOR plus 4%, due in December 2018 8,189 13,063 REG Mason City term loan, fixed interest rate of 5%, due in July 2019 1,153 2,659 REG Ralston term loan, fixed interest rate of 5%, due in October 2025 6,183 — REG Ames term loans, secured, fixed interest rates of 3.5% and 4.25%, due in January 2018 and December 2019, respectively — 3,565 REG Grays Harbor term loan, variable interest of minimum 3.5% or Prime Rate plus 0.25%, due in May 2022 7,882 9,273 REG Capital term loan, fixed interest rate of 3.99%, due in January 2028 7,400 — Other 179 468 Total debt before debt issuance costs 228,560 217,891 Less: Current portion of long-term debt 13,397 15,402 Less: Debt issuance costs (net of accumulated amortization of $3,510 and $2,396, respectively) 6,627 6,286 Total long-term debt $ 208,536 $ 196,203
Summary of company's revolving borrowings	The Company’s revolving debt at December 31 are as follows: 2017 2016 Total revolving loans (current) $ 65,525 $ 52,844 Maximum remaining available to be borrowed under revolving lines of credit $ 60,839 $ 100,237
Summary of maturities of the term borrowings	Maturities of the term debt, including the convertible debt, are as follows for the years ending December 31: 2018 $ 13,397 2019 76,856 2020 6,824 2021 5,613 2022 3,548 Thereafter 122,322 Total term debt 228,560 Less: current portion 13,397 Total long-term debt $ 215,163

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income tax benefit (expense)	Income tax benefit (expense) for the years ended December 31 is as follows: 2017 2016 2015 Current income tax benefit (expense) Federal $ — $ — $ — State (45 ) 94 — Foreign 421 (1,036 ) (225 ) 376 (942 ) (225 ) Deferred income tax benefit (expense) Federal 22,619 2,113 24,151 State 10,282 6,936 9,736 Foreign 2,674 (2,560 ) 1,035 Change in enacted tax rates (123,289 ) — — Net operating loss carryforwards created 17,466 105,165 88,110 (70,248 ) 111,654 123,032 Income tax benefit (expense) before valuation allowances (69,872 ) 110,712 122,807 Deferred tax valuation allowances 100,362 (114,980 ) (114,106 ) Income tax benefit (expense) $ 30,490 $ (4,268 ) $ 8,701
Effective income tax rate continuing operations tax rate reconciliation	A reconciliation of the reported amount of income tax expense to the amount computed by applying the statutory federal income tax rate to earnings from continuing operations before income taxes is as follows: 2017 2016 2015 U.S. Federal income tax expense at a statutory rate of 35 percent $ 38,349 $ (17,143 ) $ 56,144 State taxes, net of federal income tax benefit 8,160 11,442 12,777 Tax position on government incentives 9,402 117,630 85,423 Change in enacted tax rates (123,289 ) — — Goodwill impairment tax impact — 2,876 (35,062 ) Bargain purchase gain — — 1,875 Foreign net operating loss expiration — (2,383 ) — Other (2,494 ) (1,710 ) 1,650 Total (expense) benefits for income taxes before valuation allowances (69,872 ) 110,712 122,807 Valuation allowances 100,362 (114,980 ) (114,106 ) Total benefit (expense) for income taxes $ 30,490 $ (4,268 ) $ 8,701
Tax effects of temporary differences that give rise to the Company's deferred tax assets and liabilities	The tax effects of temporary differences that give rise to the Company’s deferred tax assets and liabilities at December 31 are as follows: 2017 2016 Deferred Tax Assets: Net operating loss carryforwards $ 249,371 $ 346,768 Goodwill 26,448 42,082 Capitalized research and development 9,788 11,394 Stock-based compensation 3,924 5,853 Risk management unrealized gain (loss) 1,879 874 Tax credit carryforwards 1,597 1,597 Accrued compensation 1,062 4,419 Inventory capitalization 1,491 3,227 Other 2,945 6,623 Deferred tax assets 298,505 422,837 Deferred Tax Liabilities: Property, plant and equipment (27,314 ) (61,431 ) Convertible debt (9,889 ) (5,797 ) Intangibles (2,195 ) (3,591 ) Prepaid expenses (1,393 ) (1,724 ) Deferred revenue — (3,454 ) Other (544 ) (2,084 ) Deferred tax liabilities (41,335 ) (78,081 ) Net deferred tax assets (liabilities) 257,170 344,756 Valuation allowance (265,362 ) (365,035 ) Net deferred tax liabilities $ (8,192 ) $ (20,279 )
Valuation allowance for deferred tax assets	Activity regarding the valuation allowance for deferred tax assets was as follows: 2017 2016 2015 Beginning of year balance $ 365,035 $ 250,164 $ 136,547 Changes in valuation allowance charged to income 36,639 114,980 114,106 Change in enacted tax rates (137,001 ) — — Foreign currency translation 689 (109 ) (773 ) Acquisition — — 284 End of year balance $ 265,362 $ 365,035 $ 250,164
Reconciliation of total amounts of unrecognized tax benefits	A reconciliation of the total amounts of unrecognized tax benefits at December 31 is as follows: 2017 2016 2015 Beginning of year balance $ 1,900 $ 1,900 $ 1,900 Decreases to tax positions taken during prior years (129 ) — — End of year balance $ 1,771 $ 1,900 $ 1,900

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary about the Company's Common Stock restricted stock units granted, vested, exercised and forfeited	The following table summarizes information about the Company’s Common Stock RSU’s granted, vested, exercised and forfeited: Number of Awards Weighted Average Issue Price Awards outstanding - January 1, 2015 616,394 $15.00 Issued 339,280 $9.34 Vested and restriction lapsed (295,089 ) $9.36 Forfeited (22,687 ) $10.56 Awards outstanding - December 31, 2015 637,898 $12.87 Issued 504,647 $9.07 Vested and restriction lapsed (249,356 ) $9.77 Forfeited (33,938 ) $8.15 Awards outstanding - December 31, 2016 859,251 $11.73 Issued 360,741 $11.91 Vested and restriction lapsed (204,198 ) $11.05 Forfeited (127,403 ) $10.04 Awards outstanding - December 31, 2017 888,391 $12.12
Summary about the Company's Common Stock performance restricted stock units granted, vested, exercised and forfeited	The following table summarizes information about the Company’s Common Stock RSU’s granted, vested, exercised and forfeited: Number of Awards Weighted Average Issue Price Awards outstanding -January 1, 2015 — $ — Issued 59,623 $ 9.40 Vested and restriction lapsed — $ — Forfeited — $ — Awards outstanding - December 31, 2015 59,623 $ 9.40 Issued 175,217 $ 9.06 Vested and restriction lapsed — $ — Forfeited — $ — Awards outstanding - December 31, 2016 234,840 $ 9.15 Issued 270,765 $ 11.79 Vested and restriction lapsed (87,622 ) $ 11.75 Forfeited (62,865 ) $ 9.48 Awards outstanding - December 31, 2017 355,118 $ 10.46
Summary about the stock appreciate rights granted, forfeited, vested and exercisable	The following table summarizes information about SARs granted, forfeited, vested and exercisable: Number of SAR’s Weighted Average Exercise Price Weighted Average Contractual Term SAR's outstanding - January 1, 2015 1,809,302 $10.63 Granted 655,855 $9.47 Exercised (14,470 ) $9.21 Forfeited (54,561 ) $10.30 SAR's outstanding - December 31, 2015 2,396,126 $10.33 7.6 years Granted 176,824 $8.80 Exercised (8,003 ) $8.57 Forfeited (56,932 ) $10.75 SAR's outstanding - December 31, 2016 2,508,015 $10.22 6.7 years Granted — Exercised (700,765 ) $10.36 Forfeited (105,981 ) $9.66 SAR's outstanding - December 31, 2017 1,701,269 $10.20 5.7 years SAR's exercisable - December 31, 2017 1,247,161 $10.34 5.7 years SAR's expected to vest - December 31, 2017 863,626 $10.40 5.7 years
Assumptions for Black-Scholes options pricing model/Estimated fair value of SAR grant using Black-Scholes options pricing model	The fair value of each SAR grant is estimated using the Black-Scholes option-pricing model as set forth in the table below: 2017 2016 2015 The weighted average fair value of stock appreciation rights issued (per unit) $2.79 - $3.74 $2.79 - $3.74 $3.33 - $3.90 Dividend yield —% —% —% Weighted average risk-free interest rate 1.1% - 1.4% 1.1% - 1.4% 1.4% - 1.6% Weighted average expected volatility 40% 40% 40% Expected life in years 6.25 6.25 6.25
Common Stock options granted, exercised, forfeited, vested and exercisable	At the end of December 31, 2014 and 2015, there were 87,026 options outstanding at $23.75 /share. Such options were forfeited during 2016.

Operating Leases (Tables)

Operating Leases (Tables)	12 Months Ended
	Dec. 31, 2017
Leases, Operating [Abstract]
Future minimum lease payments under operating leases	For each of the next five calendar years and thereafter, future minimum lease payments under operating leases that have initial or remaining noncancelable lease terms in excess of one year are as follows: Total Payments 2018 $ 17,032 2019 14,243 2020 9,330 2021 8,900 2022 2,052 Thereafter 14,953 Total minimum payments $ 66,510

Derivative Instruments (Tables)

Derivative Instruments (Tables)	12 Months Ended
	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Summary of Derivative Financial Instruments by Balance Sheet Location	The following tables provide details regarding the Company’s derivative financial instruments: December 31, 2017 December 31, 2016 Assets Liabilities Assets Liabilities Gross amounts of commodity derivative contracts recognized at fair value $ 812 $ 8,001 $ 1,272 $ 3,511 Cash collateral 8,799 — 9,366 — Total gross amount recognized 9,611 8,001 10,638 3,511 Gross amounts offset (8,001 ) (8,001 ) (3,511 ) (3,511 ) Net amount reported in the Consolidated Balance Sheets $ 1,610 $ — $ 7,127 $ —
Summary of Derivative Financial Instruments by Location of Gain (Loss)	The following table sets forth the pre-tax gains (losses) included in the Consolidated Statements of Operations: Location of Gain (Loss) 2017 2016 2015 Commodity derivatives Cost of goods sold – Biomass-based diesel $ (23,437 ) $ (35,386 ) $ 35,983

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Assets (liabilities) measured at fair value	A summary of assets (liabilities) measured at fair value is as follows: As of December 31, 2017 Total Level 1 Level 2 Level 3 Commodity contract derivatives $ (7,189 ) $ (3,742 ) $ (3,447 ) $ — Contingent consideration for acquisitions $ (34,393 ) — — (34,393 ) $ (41,582 ) $ (3,742 ) $ (3,447 ) $ (34,393 ) As of December 31, 2016 Total Level 1 Level 2 Level 3 Commodity contract derivatives $ (2,239 ) (1,297 ) (942 ) — Convertible debt conversion liability $ (27,100 ) — (27,100 ) — Contingent consideration for acquisitions $ (46,568 ) — — (46,568 ) $ (75,907 ) $ (1,297 ) $ (28,042 ) $ (46,568 )
Liabilities measured at fair value on a recurring basis	The following is a reconciliation of the beginning and ending balances for liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) during the years ended as follows: Contingent Consideration for Acquisitions 2017 2016 Balance at beginning of period, January 1 $ 46,568 $ 41,712 Fair value of contingent consideration at measurement date — 4,500 Change in estimates included in earnings 2,484 7,904 Settlements (14,659 ) (7,548 ) Balance at end of period, December 31 $ 34,393 $ 46,568
Estimated fair values of the Company's financial instruments	The estimated fair values of the Company’s financial instruments, which are not recorded at fair value are as follows as of December 31: 2017 2016 Asset (Liability) Carrying Amount Estimated Fair Value Asset (Liability) Carrying Amount Estimated Fair Value Financial Liabilities: Debt and lines of credit $ (294,085 ) $ (273,983 ) $ (270,735 ) $ (264,267 )

Net Income (Loss) Per Share (Ta

Net Income (Loss) Per Share (Tables)	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Dilutive weighted average securities were excluded from the calculation of diluted net income (loss) per share attributable to common stockholders during the periods	The following potentially dilutive average number of securities were excluded from the calculation of diluted net income per share attributable to common stockholders during the periods presented as the effect was anti-dilutive: Year Ended December 31, 2017 2016 2015 Options to purchase common stock — 43,513 87,026 Stock appreciation rights 622,633 2,422,716 2,072,130 2019 Convertible notes 5,567,112 7,895,675 10,838,218 2036 Convertible notes 14,106,725 8,209,651 — Total 20,296,470 18,571,555 12,997,374
Calculation of diluted net income per share	The following table presents the calculation of diluted net income per share for the years ended December 31, 2017 , 2016 and 2015 (in thousands, except share and per share data): 2017 2016 2015 Net income (loss) attributable to the Company's common stockholders - Basic $ (79,079 ) $ 43,453 $ (151,392 ) Plus (less): effect of participating securities — 874 — Net income (loss) attributable to common stockholders (79,079 ) 44,327 (151,392 ) Less: effect of participating securities — (874 ) — Net income (loss) attributable to the Company's common stockholders - Diluted $ (79,079 ) $ 43,453 $ (151,392 ) Shares: Weighted-average shares outstanding - Basic 38,731,015 40,897,549 43,958,803 Adjustment to reflect stock appreciation right conversions — 5,311 — Weighted-average shares outstanding - Diluted 38,731,015 40,902,860 43,958,803 Net income (loss) per share attributable to common stockholders - Diluted $ (2.04 ) $ 1.06 $ (3.44 )

Reportable Segments and Geogr45

Reportable Segments and Geographic Information (Tables)	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Segment for the results of operations	The following table represents the significant items by reportable segment for the results of operations for the years ended December 31, 2017 , 2016 and 2015 : 2017 2016 2015 Net sales: Biomass-based Diesel (includes REG Germany's net sales of $171,175, $171,358, and $145,039, respectively) $ 2,039,982 $ 1,952,361 $ 1,326,452 Services 103,215 87,014 102,731 Renewable Chemicals 4,531 2,065 — Corporate and other 212,557 106,572 68,984 Intersegment revenues (202,042 ) (106,780 ) (110,823 ) $ 2,158,243 $ 2,041,232 $ 1,387,344 Income (loss) before income taxes Biomass-based diesel (includes REG Germany's income (loss) of ($7,544), $5,007, and $(1,643), respectively) $ (63,925 ) $ 64,814 $ (100,152 ) Services 2,899 2,970 6,323 Renewable Chemicals (19,326 ) (19,787 ) (52,728 ) Corporate and other (29,217 ) 984 (13,854 ) $ (109,569 ) $ 48,981 $ (160,411 ) Depreciation and amortization expense, net: Biomass-based diesel (includes REG Germany's amounts of $2,990, $2,849, and $3,259, respectively) $ 31,011 $ 29,018 $ 22,799 Services 1,092 613 302 Renewable Chemicals 2,666 1,550 1,413 Corporate and other 2,167 1,696 1,362 $ 36,936 $ 32,877 $ 25,876 Cash paid for purchases of property, plant and equipment: Biomass-based diesel (includes REG Germany's amounts of $3,241, $1,353, and $1,816, respectively) $ 60,734 $ 52,952 $ 59,859 Services 3,826 4,731 1,510 Renewable Chemicals 14 473 672 Corporate and other 2,998 2,549 2,436 $ 67,572 $ 60,705 $ 64,477 2017 2016 Goodwill: Biomass-based diesel $ — $ — Services 16,080 16,080 Renewable Chemicals — — $ 16,080 $ 16,080 Assets: Biomass-based diesel (including REG Germany's assets of $55,761 and $51,822) $ 898,180 $ 1,026,349 Services 55,581 53,823 Renewable Chemicals 21,168 22,883 Corporate and other 386,590 299,825 Intersegment eliminations (355,923 ) (266,277 ) $ 1,005,596 $ 1,136,603
Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas	The following geographic data include net sales attributed to the countries based on the location of the subsidiaries making the sale and long-lived assets based on physical location. Long-lived assets represent the net book value of property, plant and equipment. 2017 2016 2015 Net sales: United States $ 1,961,303 $ 1,869,874 $ 1,242,305 Germany 171,175 171,358 — 145,039 Other Foreign 25,765 — — Total Foreign 196,940 171,358 145,039 $ 2,158,243 $ 2,041,232 $ 1,387,344 2017 2016 Long-lived assets: United States 566,028 580,868 Germany 20,689 18,472 Other Foreign 680 134 Total Foreign 21,369 18,606 587,397 599,474

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Contractual Obligation, Fiscal Year Maturity Schedule	The following table outlines the minimum take or pay requirement related to the purchase of hydrogen, nitrogen, utilities and natural gas. 2018 $ 3,784 2019 3,748 2020 3,297 2021 2,976 2022 2,976 Thereafter 6,798 Total $ 23,579

Supplemental Quarterly Inform47

Supplemental Quarterly Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Significant items for the results of operations on a quarterly basis	The following table represents the significant items for the results of operations on a quarterly basis for the years ended December 31, 2017 and 2016 : Three Months Three Months Three Months Three Months Revenues $ 418,893 $ 535,103 $ 626,983 $ 577,264 Gross profit (loss) 17,283 31,454 14,795 20,049 Selling, general, and administrative expenses including research and development expense 26,505 25,993 29,639 25,379 Impairment of property, plant and equipment — 1,341 — 48,532 Net income (loss) from operations (9,222 ) 4,120 (14,844 ) (53,862 ) Other income (expense), net (5,617 ) (36,969 ) 3,356 3,469 Net income (loss) attributable to the Company (15,914 ) (34,809 ) (11,373 ) (16,983 ) Net income (loss) per share attributable to common stockholders - basic (0.41 ) (0.90 ) (0.29 ) (0.44 ) Net income (loss) per share attributable to common stockholders - diluted (0.41 ) (0.90 ) (0.29 ) (0.44 ) Three Months Three Months Three Months Three Months Revenues $ 297,870 $ 558,301 $ 624,640 $ 560,421 Gross profit (loss) 17,384 24,862 47,350 81,920 Selling, general, and administrative expenses including research and development expense 23,703 25,277 25,604 31,864 Impairment of property, plant and equipment — — — 17,893 Net income (loss) from operations (6,319 ) (415 ) 21,746 32,163 Other income (expense), net 159 7,432 558 (6,343 ) Net income (loss) attributable to the Company (6,918 ) 7,606 23,442 20,197 Net income (loss) per share attributable to common stockholders - basic (0.16 ) 0.18 0.59 0.51 Net income (loss) per share attributable to common stockholders - diluted (0.14 ) 0.18 0.59 0.51

Organization, Presentation, a48

Organization, Presentation, and Nature of the Business - (Details) gal in Millions	12 Months Ended
	Dec. 31, 2017facilitygal	Mar. 15, 2016gal
Class of Stock [Line Items]
Number of biorefineries	14
Number of operating biodiesel production facilities	13
Production capacity per year | gal	520
Number of fermentation facilities	1
Number of feedstock processing facilities	1
Number of multi-feedstock capable plants	10
Number of non-operating biodiesel production facilities	1
Construction in Progress
Class of Stock [Line Items]
Number of operating biodiesel production facilities	3
Sanimax
Class of Stock [Line Items]
Production capacity per year | gal	20	20
North America
Class of Stock [Line Items]
Number of biorefineries	12
Europe
Class of Stock [Line Items]
Number of biorefineries	2

Summary of Significant Accoun49

Summary of Significant Accounting Policies - Accounts Receivable (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Activity regarding the allowance for doubtful accounts
Balance, beginning of period	$ 1,875	$ 1,351	$ 2,273
Amount charged to selling, general and administrative expenses	139	630	(803)
Charge-offs, net of recoveries	(779)	(106)	(119)
Balance, end of period	$ 1,235	$ 1,875	$ 1,351

Summary of Significant Accoun50

Summary of Significant Accounting Policies - (Details Textual)	1 Months Ended		3 Months Ended								7 Months Ended	12 Months Ended			21 Months Ended	24 Months Ended
	Jun. 30, 2017USD ($)a	Jun. 30, 2016shares	Dec. 31, 2017USD ($)	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)a	Mar. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2017USD ($)renewable_identification_numbershares	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)customer	Dec. 31, 2016USD ($)	Dec. 31, 2017USD ($)	Jun. 02, 2016USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Biomass-based diesel government incentives												$ 28,728,000	$ 346,672,000	$ 245,868,000
Accounts receivable, net			$ 90,648,000				$ 164,949,000				$ 90,648,000	90,648,000	164,949,000		$ 164,949,000	$ 90,648,000
Estimated impaired fixed assets											2,671,000
Insurance recoveries			5,000,000	$ 3,000,000								8,000,000			19,037,000
Proceeds from business interruption insurance												2,000,000
Adjacent land purchased | a	61				61
Payments for land acquisition	$ 20,000,000
Lease termination loss					$ (3,967,000)
Capitalization of interest incurred on debt during construction			301,000				537,000				301,000	301,000	537,000	897,000	537,000	301,000
Impairment of goodwill												0	0	175,028,000
Impairment of property, plant and equipment, net			48,532,000	$ 0	1,341,000	$ 0	17,893,000	$ 0	$ 0	$ 0		49,873,000	17,893,000	0
Impairment charges due to deteriorating physical condition												5,224,000	2,300,000
Fair value of embedded conversion option												27,908,000
Tax impact of 2036 Senior Notes conversion liability reclassification												18,025,000
Change in fair value of convertible debt conversion liability												$ (18,833,000)	13,045,000	0
Shares covered by rebalancing call options												100.00%
Revenues associated with government incentive programs												$ 607,000	434,000	624,000
Advertising and promotional expenses												2,140,000	1,746,000	1,288,000
Impairment of IPR&D												$ 0	0	0
Matching contributions												50.00%
Participants eligible earnings												6.00%
Total expense related to the Company's defined contribution plan												$ 1,367,000	1,168,000	$ 1,071,000
Cash, coverage by U.S. FDIC			250,000								250,000	$ 250,000				250,000
Share repurchase program, shares repurchased (in shares) | shares												0
Customer A
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of customers | customer														1
March 2,016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock repurchase program, amount authorized to be repurchased			75,000,000								75,000,000	$ 75,000,000				75,000,000
Convertible Senior Notes | 2036 Convertible Notes
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Face amount	$ 152,000,000				$ 152,000,000												$ 152,000,000
Interest rate	4.00%				4.00%												4.00%
Fair value of embedded conversion option												45,933,000
Tax impact of 2036 Senior Notes conversion liability reclassification												$ 18,025,000
Share repurchase program, shares repurchased (in shares) | shares		4,060,323
Services
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum percentage increase in fair value of each of the reporting units over its carrying value through annual impairment test												49.00%
New Orleans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Impairment of property, plant and equipment, net			44,649,000									$ 44,649,000
Emporia
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Impairment of property, plant and equipment, net													15,593,000
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RINs per gallon | renewable_identification_number												1.5
Allowed RINs per gallon | renewable_identification_number												0
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RINs per gallon | renewable_identification_number												1.7
Allowed RINs per gallon | renewable_identification_number												2.5
In-process research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Useful life												15 years
Biodiesel Mixture Excise Tax Credit
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Biomass-based diesel government incentives																86,504,000
Accounts receivable, net			$ 2,762,000				$ 89,266,000				$ 2,762,000	$ 2,762,000	$ 89,266,000		$ 89,266,000	$ 2,762,000

Summary of Significant Accoun51

Summary of Significant Accounting Policies - Property, Plant and Equipment (Details)	12 Months Ended
	Dec. 31, 2017
Automobiles and trucks
Estimated useful lives
Estimated useful lives	5 years
Computers and office equipment
Estimated useful lives
Estimated useful lives	5 years
Office furniture and fixtures
Estimated useful lives
Estimated useful lives	7 years
Machinery and equipment | Minimum
Estimated useful lives
Estimated useful lives	5 years
Machinery and equipment | Maximum
Estimated useful lives
Estimated useful lives	30 years
Leasehold improvements
Estimated useful lives
Estimated useful lives	30 years
Buildings and improvements | Minimum
Estimated useful lives
Estimated useful lives	30 years
Buildings and improvements | Maximum
Estimated useful lives
Estimated useful lives	40 years

Summary of Significant Accoun52

Summary of Significant Accounting Policies - Concentrations (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Concentration Risk [Line Items]
Revenues	$ 577,264	$ 626,983	$ 535,103	$ 418,893	$ 560,421	$ 624,640	$ 558,301	$ 297,870	$ 2,158,243	$ 2,041,232	$ 1,387,344
Customer A
Concentration Risk [Line Items]
Revenues									$ 182,236	$ 144,849	$ 114,030

Stockholders' Equity of the C53

Stockholders' Equity of the Company - (Details Textual) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Capital Stock
Common stock, shares authorized (in shares)	450,000,000
Common Stock | Initial public offering
Common stock, shares authorized (in shares)	300,000,000
Class A Common Stock
Common stock, shares authorized (in shares)	140,000,000
Preferred Stock
Preferred stock (in shares)	10,000,000
Series B Preferred Stock
Preferred stock (in shares)	3,000,000

Acquisitions - (Details Textual

Acquisitions - (Details Textual) $ in Thousands, gal in Millions	Mar. 15, 2016USD ($)sharesgal	Aug. 19, 2015USD ($)sharesgal	Dec. 31, 2017USD ($)gal	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Business Acquisition [Line Items]
Production capacity per year | gal			520
Contingent consideration			$ 8,849	$ 28,931
Contingent consideration, current portion			25,545	17,637
Bargain purchase gain			$ 0	$ 0	$ 5,358
Sanimax
Business Acquisition [Line Items]
Production capacity per year | gal	20		20
Shares of Common Stock issued (in shares) | shares	500,000
Contingent consideration	$ 5,000		$ 2,603
Earnout payment period	7 years
Maximum Earnout Payments per year	$ 1,700
Contingent consideration, current portion			$ 1,160
Imperium Renewables, Inc.
Business Acquisition [Line Items]
Production capacity per year | gal		100
Shares of Common Stock issued (in shares) | shares		1,675,000
Earnout payment period		2 years
Bargain purchase gain		$ 5,358

Acquisitions - (Details)

Acquisitions - (Details) - USD ($) $ in Thousands	Mar. 15, 2016	Aug. 19, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Cash			$ 3,482	$ 12,720	$ 41,409
Summary of allocations of the purchase price to the fair values of the assets acquired and liabilities assumed at the date of acquisition
Debt			0	0	(5,225)
Bargain purchase gain			$ 0	$ 0	$ 5,358
Sanimax
Business Acquisition [Line Items]
Cash	$ 12,541
Common stock	4,050
Contingent consideration	4,500
Total	21,091
Summary of allocations of the purchase price to the fair values of the assets acquired and liabilities assumed at the date of acquisition
Inventory	1,591
Property, plant and equipment	19,500
Total identifiable assets acquired	21,091
Accrued expenses and other liabilities	0
Net identifiable assets acquired	$ 21,091
Imperium Renewables, Inc.
Business Acquisition [Line Items]
Cash		$ 36,748
Common stock		15,310
Contingent consideration		5,000
Total		57,058
Summary of allocations of the purchase price to the fair values of the assets acquired and liabilities assumed at the date of acquisition
Cash		168
Accounts receivable		8,274
Inventory		18,989
Other current assets		87
Property, plant and equipment		46,476
Intangible assets		2,900
Total identifiable assets acquired		76,894
Accounts payable		(4,828)
Accrued expenses and other liabilities		(942)
Debt		(5,225)
Deferred tax liabilities		(3,483)
Total liabilities assumed		(14,478)
Net identifiable assets acquired		62,416
Bargain purchase gain		5,358
Net assets acquired		$ 57,058

Acquisitions - Pro Forma (Detai

Acquisitions - Pro Forma (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Combinations [Abstract]
Revenues	$ 2,158,243	$ 2,049,658	$ 1,406,580
Net income (loss) attributable to the Company's common stockholders	$ (79,079)	$ 43,453	$ (157,524)
Basic net income (loss) per share attributable to common stockholders (in dollars per share)	$ (2.04)	$ 1.06	$ (3.50)

Inventories - (Details)

Inventories - (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Inventories
Raw materials	$ 39,975	$ 34,560
Work in process	3,523	3,775
Finished goods	92,049	107,073
Total	$ 135,547	$ 145,408

Property, Plant and Equipment -

Property, Plant and Equipment - (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, plant and equipment
Property, Plant and Equipment	$ 696,538				$ 661,791				$ 696,538	$ 661,791
Accumulated depreciation	(175,531)				(138,372)				(175,531)	(138,372)
Property plant and equipment net excluding construction in progress	521,007				523,419				521,007	523,419
Construction in process	66,390				76,055				66,390	76,055
Total	587,397				599,474				587,397	599,474
Impairment of property, plant and equipment	48,532	$ 0	$ 1,341	$ 0	17,893	$ 0	$ 0	$ 0	49,873	17,893	$ 0
New Orleans
Property, plant and equipment
Impairment of property, plant and equipment	44,649								44,649
Emporia
Property, plant and equipment
Impairment of property, plant and equipment										15,593
Land
Property, plant and equipment
Property, Plant and Equipment	10,480				5,412				10,480	5,412
Buildings and improvements
Property, plant and equipment
Property, Plant and Equipment	140,261				134,398				140,261	134,398
Leasehold improvements
Property, plant and equipment
Property, Plant and Equipment	10,806				10,520				10,806	10,520
Machinery and equipment
Property, plant and equipment
Property, Plant and Equipment	$ 534,991				$ 511,461				$ 534,991	$ 511,461

Intangible Assets - (Details)

Intangible Assets - (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Components of Intangible assets
Cost	$ 33,586	$ 33,586
Accumulated amortization	(6,459)	(4,116)
Net	27,127	29,470
In-process research and development
Components of Intangible assets
Cost		15,956
Accumulated amortization		(177)
Net		$ 15,779
Weighted Average Remaining Life		14 years 10 months
Raw material supply agreement
Components of Intangible assets
Cost	6,230	$ 6,230
Accumulated amortization	(2,408)	(1,987)
Net	$ 3,822	$ 4,243
Weighted Average Remaining Life	8 years	9 years
Renewable diesel technology
Components of Intangible assets
Cost	$ 8,300	$ 8,300
Accumulated amortization	(1,983)	(1,429)
Net	$ 6,317	$ 6,871
Weighted Average Remaining Life	11 years 6 months	12 years 6 months
Acquired customer relationships
Components of Intangible assets
Cost	$ 2,900	$ 2,900
Accumulated amortization	(686)	(396)
Net	$ 2,214	$ 2,504
Weighted Average Remaining Life	7 years 7 months 15 days	8 years 7 months 15 days
Ground lease
Components of Intangible assets
Cost	$ 200	$ 200
Accumulated amortization	(141)	(127)
Net	$ 59	$ 73
Weighted Average Remaining Life	3 years 10 months 24 days	4 years 10 months 24 days
In-process research and development
Components of Intangible assets
Cost	$ 15,956
Accumulated amortization	(1,241)
Net	$ 14,715
Weighted Average Remaining Life	13 years 10 months

Intangible Assets - (Details Te

Intangible Assets - (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Indefinite-lived Intangible Assets [Line Items]
Amortization expense	$ 2,343	$ 1,471	$ 1,112
Raw material supply agreement
Indefinite-lived Intangible Assets [Line Items]
Useful life	15 years

Intangible Assets - Estimated A

Intangible Assets - Estimated Amortization Expense (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Estimated amortization expense
2,018	$ 2,425
2,019	2,433
2,020	2,440
2,021	2,447
2,022	2,441
Thereafter	14,941
Net	$ 27,127	$ 29,470

Other Assets - (Details)

Other Assets - (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Summary of prepaid expense and other current assets
Commodity derivatives and related collateral, net	$ 1,610	$ 7,127
Prepaid expenses	11,733	10,665
Deposits	2,899	2,897
RIN inventory	27,028	9,398
Taxes receivable	6,356	4,539
Other	2,254	1,646
Total	$ 51,880	$ 36,272

Other Assets - (Details Textual

Other Assets - (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
RIN
Inventory [Line Items]
Inventory reduced to lower of cost or market	$ 2,629	$ 612

Other Assets - Other Noncurrent

Other Assets - Other Noncurrent Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Summary of other noncurrent assets
Spare parts inventory	$ 2,764	$ 3,532
Catalysts	2,962	4,479
Deposits	381	2,392
Other	933	2,227
Total	$ 7,040	$ 12,630

Accrued Expenses and Other Li65

Accrued Expenses and Other Liabilities - (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Summary of accrued expenses and other liabilities
Accrued property taxes	$ 1,353	$ 1,518
Accrued employee compensation	8,172	15,005
Accrued interest	590	537
Contingent consideration, current portion	25,545	17,637
Unfavorable lease obligation, current portion	1,129	1,828
Excise tax payable	1,046	1,603
Income tax payable	455	0
Other	897	788
Total	$ 39,187	$ 38,916

Accrued Expenses and Other Li66

Accrued Expenses and Other Liabilities - Other Noncurrent Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Summary of other noncurrent liabilities
Severance payable	$ 603	$ 0
Straight-line lease liability	1,801	2,421
Asset retirement obligations	593	1,140
Other	1,117	1,295
Total	$ 4,114	$ 4,856

Debt - (Details)

Debt - (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2017	Jul. 31, 2017	Apr. 19, 2017	Dec. 31, 2016
Line of Credit Facility [Line Items]
Total debt before debt issuance costs	$ 228,560,000	$ 228,560,000			$ 217,891,000
Less: Current portion of long-term debt	13,397,000	13,397,000			15,402,000
Less: Debt issuance costs (net of accumulated amortization of $3,510 and $2,396, respectively)	6,627,000	6,627,000			6,286,000
Accumulated amortization on debt issuance costs	3,510,000	3,510,000			2,296,000
Total long-term debt	208,536,000	208,536,000			196,203,000
4.00% Convertible Senior Notes, $152,000 face amount, due in June 2036
Line of Credit Facility [Line Items]
Total debt before debt issuance costs	$ 116,255,000	$ 116,255,000			113,446,000
Interest rate	4.00%	4.00%
Face amount	$ 152,000,000	$ 152,000,000
2.75% Convertible Senior Notes, $73,838 face amount, due in June 2019
Line of Credit Facility [Line Items]
Total debt before debt issuance costs	$ 69,859,000	$ 69,859,000			67,254,000
Interest rate	2.75%	2.75%
Face amount	$ 73,838,000	$ 73,838,000
REG Danville term loan, secured, variable interest rate of LIBOR plus 4%, due in July 2022
Line of Credit Facility [Line Items]
Total debt before debt issuance costs	$ 11,460,000	$ 11,460,000			8,163,000
Face amount			$ 12,500,000
Description of variable rate		LIBOR plus 4% per annum
REG Danville term loan, secured, variable interest rate of LIBOR plus 4%, due in July 2022 | LIBOR
Line of Credit Facility [Line Items]
Variable interest rate	5.38%	4.00%
REG Newton term loan, secured, variable interest rate of LIBOR plus 4%, due in December 2018
Line of Credit Facility [Line Items]
Total debt before debt issuance costs	$ 8,189,000	$ 8,189,000			13,063,000
Description of variable rate		LIBOR plus 4% per annum
REG Newton term loan, secured, variable interest rate of LIBOR plus 4%, due in December 2018 | LIBOR
Line of Credit Facility [Line Items]
Variable interest rate		4.00%
REG Mason City term loan, fixed interest rate of 5%, due in July 2019
Line of Credit Facility [Line Items]
Total debt before debt issuance costs	$ 1,153,000	$ 1,153,000			2,659,000
Interest rate	5.00%	5.00%
REG Ralston term loan, fixed interest rate of 5%, due in October 2025
Line of Credit Facility [Line Items]
Total debt before debt issuance costs	$ 6,183,000	$ 6,183,000			0
Interest rate	5.00%	5.00%
Face amount				$ 20,000,000
REG Ralston term loan, fixed interest rate of 5%, due in October 2025 | Prime Rate
Line of Credit Facility [Line Items]
Variable interest rate	5.00%	0.50%
REG Ames term loans, secured, fixed interest rates of 3.5% and 4.25%, due in January 2018 and December 2019, respectively
Line of Credit Facility [Line Items]
Total debt before debt issuance costs	$ 0	$ 0			3,565,000
REG Ames term loans, secured, fixed interest rates of 3.5% and 4.25%, due in January 2018 and December 2019, respectively | Minimum
Line of Credit Facility [Line Items]
Interest rate	3.50%	3.50%
REG Ames term loans, secured, fixed interest rates of 3.5% and 4.25%, due in January 2018 and December 2019, respectively | Maximum
Line of Credit Facility [Line Items]
Interest rate	4.25%	4.25%
REG Grays Harbor term loan, variable interest of minimum 3.5% or Prime Rate plus 0.25%, due in May 2022
Line of Credit Facility [Line Items]
Total debt before debt issuance costs	$ 7,882,000	$ 7,882,000			9,273,000
Description of variable rate		Minimum 3.5% or Prime Rate plus 0.25%
REG Grays Harbor term loan, variable interest of minimum 3.5% or Prime Rate plus 0.25%, due in May 2022 | Prime Rate
Line of Credit Facility [Line Items]
Variable interest rate		0.25%
REG Grays Harbor term loan, variable interest of minimum 3.5% or Prime Rate plus 0.25%, due in May 2022 | Minimum
Line of Credit Facility [Line Items]
Interest rate	3.50%	3.50%
REG Capital term loan, fixed interest rate of 3.99%, due in January 2028
Line of Credit Facility [Line Items]
Total debt before debt issuance costs	$ 7,400,000	$ 7,400,000			0
Interest rate	3.99%	3.99%
Face amount	$ 7,400,000	$ 7,400,000
Other
Line of Credit Facility [Line Items]
Total debt before debt issuance costs	$ 179,000	$ 179,000			$ 468,000

Debt - (Details Textual)

Debt - (Details Textual)	Dec. 31, 2017USD ($)	Jun. 02, 2016USD ($)$ / shares	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)shares	Sep. 30, 2016USD ($)	Dec. 31, 2017USD ($)shares	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 08, 2017USD ($)	Sep. 30, 2017USD ($)	Jul. 31, 2017USD ($)	Jun. 30, 2017USD ($)	Apr. 19, 2017USD ($)
Short-term Debt [Line Items]
Convertible debt conversion liability	$ 0					$ 0	$ 27,100,000
Notes payable	228,560,000					$ 228,560,000	217,891,000
Share repurchase program, shares repurchased (in shares) | shares						0
Gain on debt extinguishment						$ 0	2,331,000	$ 0
Wells Fargo Revolver
Short-term Debt [Line Items]
Additional increase in maximum borrowing capacity					$ 150,000,000	150,000,000
Line of credit facility limitation amount	40,000,000					$ 40,000,000				$ 50,000,000
Debt instrument, variable rate minimum						0.00%
Percentage required of total current revolving loan commitments						10.00%
Amount required of total current revolving loan commitments						$ 15,000,000
Wells Fargo Revolver | Minimum
Short-term Debt [Line Items]
LIBOR rate margin						1.75%
Fixed charge coverage ratio						100.00%
Wells Fargo Revolver | Maximum
Short-term Debt [Line Items]
LIBOR rate margin						2.25%
Fixed charge coverage ratio						150.00%
BNP Paribas
Short-term Debt [Line Items]
Line of credit	$ 25,000,000					$ 25,000,000
BNP Paribas | Minimum
Short-term Debt [Line Items]
LIBOR rate margin						1.50%
BNP Paribas | Maximum
Short-term Debt [Line Items]
LIBOR rate margin						2.00%
REG Ralston term loan, fixed interest rate of 5%, due in October 2025
Short-term Debt [Line Items]
Face amount													$ 20,000,000
Interest rate	5.00%					5.00%
Notes payable	$ 6,183,000					$ 6,183,000	0
REG Danville Term Loan
Short-term Debt [Line Items]
Face amount											$ 12,500,000
Notes payable	11,460,000					11,460,000	8,163,000
REG Capital term loan, fixed interest rate of 3.99%, due in January 2028
Short-term Debt [Line Items]
Face amount	$ 7,400,000					$ 7,400,000
Interest rate	3.99%					3.99%
Notes payable	$ 7,400,000					$ 7,400,000	$ 0
Prime Rate | REG Ralston term loan, fixed interest rate of 5%, due in October 2025
Short-term Debt [Line Items]
Basis spread on variable rate	5.00%					0.50%
LIBOR | REG Danville Term Loan
Short-term Debt [Line Items]
Basis spread on variable rate	5.38%					4.00%
2.75% Convertible Senior Notes | 2036 Convertible Notes
Short-term Debt [Line Items]
Face amount		$ 152,000,000										$ 152,000,000
Interest rate		4.00%										4.00%
Percentage of convertible senior notes principal required for repurchase		100.00%
Initial conversion rate		92.8074
Initial conversion price (in dollars per share) | $ / shares		$ 10.78
Net proceeds from debt issuance		$ 147,118,000
Fees and offering expenses		4,882,000
Convertible debt conversion liability		40,145,000							$ 45,933,000
Notes payable		111,855,000
Debt discount		$ 40,145,000
Effective interest rate		2.45%
Proceeds from offering costs used to repurchase shares of Common Stock				$ 35,101,000
Share repurchase program, shares repurchased (in shares) | shares				4,060,323
2.75% Convertible Senior Notes | 2019 Convertible Notes
Short-term Debt [Line Items]
Net proceeds from debt issuance			$ 5,584,000		$ 5,584,000							$ 61,954,000
Principal amount of debt repurchased			$ 6,000,000	$ 63,912,000
Gain on debt extinguishment						$ 2,331,000

Debt - Revolving Borrowings (De

Debt - Revolving Borrowings (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Summary of company's revolving borrowings
Total revolving loans (current)	$ 65,525	$ 52,844
Maximum remaining available to be borrowed under revolving lines of credit	$ 60,839	$ 100,237

Debt - Maturities of Borrowings

Debt - Maturities of Borrowings (Details) $ in Thousands	Dec. 31, 2017USD ($)
Summary of maturities of the term borrowings
2,018	$ 13,397
2,019	76,856
2,020	6,824
2,021	5,613
2,022	3,548
Thereafter	122,322
Total term debt	228,560
Less: current portion	13,397
Noncurrent	$ 215,163

Income Taxes - (Details Textual

Income Taxes - (Details Textual) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Non-cash tax benefit due to Tax Cuts and Jobs Act	$ 13,712,000
Re-measurement of deferred tax assets due to Tax Cuts and Jobs Act	123,289,000
Release of valuation allowances due to Tax Cuts and Jobs Act	137,001,000
Impairment of goodwill		$ 0	$ 0	$ 175,028,000
Impairment of goodwill, not tax deductible				91,961,000
Tax impact related to the non-deductible portion of the goodwill impairment change				32,186,000
Goodwill impairment tax impact		0	(2,876,000)	35,062,000
Deferred tax asset reflecting federal and state net operating losses	249,371,000	249,371,000	346,768,000
Federal net operating losses	934,137,000	$ 934,137,000
Expiration date for federal net operating losses		2,028
Unrecognized tax benefits that would affect the effective tax rate	$ 0	$ 0	$ 0	$ 0
Period for unrecognized tax benefits to increase or decrease		12 months
Interest and penalties related to unrecognized tax benefits		$ 0

Income Taxes - Income Tax Benef

Income Taxes - Income Tax Benefit (Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current income tax benefit (expense)
Federal	$ 0	$ 0	$ 0
State	(45)	94	0
Foreign	421	(1,036)	(225)
Current income tax benefit (expense)	376	(942)	(225)
Deferred income tax benefit (expense)
Federal	22,619	2,113	24,151
State	10,282	6,936	9,736
Foreign	2,674	(2,560)	1,035
Change in enacted tax rates	(123,289)	0	0
Net operating loss carryforwards created	17,466	105,165	88,110
Deferred income tax benefit (expense)	(70,248)	111,654	123,032
Income tax benefit (expense) before valuation allowances	(69,872)	110,712	122,807
Deferred tax valuation allowances	100,362	(114,980)	(114,106)
Income tax benefit (expense)	$ 30,490	$ (4,268)	$ 8,701

Income Taxes - Effective Income

Income Taxes - Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Effective Tax Rate	35.00%	35.00%	35.00%
Effective income tax rate continuing operations tax rate reconciliation
U.S. Federal income tax expense at a statutory rate of 35 percent	$ 38,349	$ (17,143)	$ 56,144
State taxes, net of federal income tax benefit	8,160	11,442	12,777
Tax position on government incentives	9,402	117,630	85,423
Change in enacted tax rates	(123,289)	0	0
Goodwill impairment tax impact	0	2,876	(35,062)
Bargain purchase gain	0	0	1,875
Foreign net operating loss expiration	0	(2,383)	0
Other	(2,494)	(1,710)	1,650
Total (expense) benefits for income taxes before valuation allowances	(69,872)	110,712	122,807
Valuation allowances	100,362	(114,980)	(114,106)
Income tax benefit (expense)	$ 30,490	$ (4,268)	$ 8,701

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Deferred Tax Assets:
Capitalized research and development	$ 249,371	$ 346,768
Goodwill	26,448	42,082
Capitalized research and development	9,788	11,394
Stock-based compensation	3,924	5,853
Risk management unrealized gain (loss)	1,879	874
Tax credit carryforwards	1,597	1,597
Accrued compensation	1,062	4,419
Inventory capitalization	1,491	3,227
Other	2,945	6,623
Deferred tax assets	298,505	422,837
Deferred Tax Liabilities:
Property, plant and equipment	(27,314)	(61,431)
Convertible debt	(9,889)	(5,797)
Intangibles	(2,195)	(3,591)
Prepaid expenses	(1,393)	(1,724)
Deferred revenue	0	(3,454)
Other	(544)	(2,084)
Deferred tax liabilities	(41,335)	(78,081)
Net deferred tax assets (liabilities)	257,170	344,756
Valuation allowance	(265,362)	(365,035)	$ (250,164)	$ (136,547)
Net deferred tax liabilities	$ (8,192)	$ (20,279)

Income Taxes - Valuation Allowa

Income Taxes - Valuation Allowance for Deferred Tax Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning of year balance	$ 365,035	$ 250,164	$ 136,547
Changes in valuation allowance charged to income	36,639	114,980	114,106
Change in enacted tax rates	(137,001)	0	0
Foreign currency translation	689	(109)	(773)
Acquisition	0	0	284
End of year balance	$ 265,362	$ 365,035	$ 250,164

Income Taxes - Unrecognized Tax

Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning of year balance	$ 1,900	$ 1,900	$ 1,900
Decreases to tax positions taken during prior years	129	0	0
End of year balance	$ 1,771	$ 1,900	$ 1,900

Stock-Based Compensation - (Det

Stock-Based Compensation - (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	May 08, 2017	May 15, 2014	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Oct. 26, 2011
Stock-Based Compensation (Textual) [Abstract]
Common Stock (in shares)	6,510,000	6,510,000					4,160,000
Number of additional shares reserved for issuance (in shares)	2,350,000	2,350,000
Stock-based compensation cost			$ 6,909	$ 5,896	$ 5,161
Unrecognized compensation expense			$ 6,221
Expected period of unrecognized compensation expense			3 years 4 months 27 days
Outstanding stock options (in shares)			0	0	87,026	87,026
Options outstanding (in dollars per share)			$ 0	$ 0	$ 23.75	$ 23.75
Restricted stock units
Stock-Based Compensation (Textual) [Abstract]
Conversion of common stock upon vesting (in shares)			1
Service period for awards			3 years
Restricted stock units | Board of Directors
Stock-Based Compensation (Textual) [Abstract]
Service period for awards			1 year
Restricted stock units | Certain executive management | Minimum
Stock-Based Compensation (Textual) [Abstract]
Service period for awards			3 years
Restricted stock units | Certain executive management | Maximum
Stock-Based Compensation (Textual) [Abstract]
Service period for awards			4 years
Performance Restricted Stock Units
Stock-Based Compensation (Textual) [Abstract]
Conversion of common stock upon vesting (in shares)			1
Service period for awards			2 years
Stock appreciation rights
Stock-Based Compensation (Textual) [Abstract]
Percentage of SARs vesting annually			25.00%
Grant expiration period			10 years

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Stock Units (Details) - Restricted Stock Units - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Number of Awards
Awards outstanding, beginning balance (in shares)	859,251	637,898	616,394
Issued (in shares)	360,741	504,647	339,280
Vested and restriction lapsed (in shares)	(204,198)	(249,356)	(295,089)
Forfeited (in shares)	(127,403)	(33,938)	(22,687)
Awards outstanding, ending balance (in shares)	888,391	859,251	637,898
Weighted Average Issue Price (in dollars per share)
Awards outstanding - beginning balance (in dollars per share)	$ 11.73	$ 12.87	$ 15
Issued (in dollars per share)	11.91	9.07	9.34
Vested and restriction lapsed (in dollars per share)	11.05	9.77	9.36
Forfeited (in dollars per share)	10.04	8.15	10.56
Awards outstanding - ending balance (in dollars per share)	$ 12.12	$ 11.73	$ 12.87

Stock-Based Compensation - Perf

Stock-Based Compensation - Performance Restricted Stock Units (Details) - Performance Restricted Stock Units - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Number of Awards
Awards outstanding, beginning balance (in shares)	234,840	59,623	0
Issued (in shares)	270,765	175,217	59,623
Vested and restriction lapsed (in shares)	(87,622)	0	0
Forfeited (in shares)	(62,865)	0	0
Awards outstanding, ending balance (in shares)	355,118	234,840	59,623
Weighted Average Issue Price (in dollars per share)
Awards outstanding - beginning balance (in dollars per share)	$ 9.15	$ 9.40	$ 0
Issued (in dollars per share)	11.79	9.06	9.40
Vested and restriction lapsed (in dollars per share)	11.75	0	0
Forfeited (in dollars per share)	9.48	0	0
Awards outstanding - ending balance (in dollars per share)	$ 10.46	$ 9.15	$ 9.40

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Appreciation Rights (Details) - Stock Appreciation Rights - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Number of SAR’s
Awards outstanding, beginning balance (in shares)	2,508,015	2,396,126	1,809,302
Granted (in shares)	0	176,824	655,855
Exercised (in shares)	(700,765)	(8,003)	(14,470)
Forfeited (in shares)	(105,981)	(56,932)	(54,561)
Awards outstanding, ending balance (in shares)	1,701,269	2,508,015	2,396,126
Number of SAR's - SAR's exercisable (in shares)	1,247,161
Number of SAR's - SAR's expected to vest (in shares)	863,626
Weighted Average Exercise Price (in dollars per share)
SAR's outstanding - beginning balance (in dollars per share)	$ 10.22	$ 10.33	$ 10.63
Granted (in dollars per share)		8.80	9.47
Exercised (in dollars per share)	10.36	8.57	9.21
Forfeited (in dollars per share)	9.66	10.75	10.30
SAR's outstanding - ending balance (in dollars per share)	10.20	$ 10.22	$ 10.33
Weighted Average Exercise Price - SAR's exercisable (in dollars per share)	10.34
Weighted Average Exercise Price - SAR's expected to vest (in dollars per share)	$ 10.40
Weighted Average Contractual Term - SAR's outstanding	5 years 8 months 12 days	6 years 8 months 12 days	7 years 7 months 6 days
Weighted Average Contractual Term - SAR's expected to vest	5 years 8 months 12 days

Stock-Based Compensation - Fair

Stock-Based Compensation - Fair Value of SAR's Using Black-Scholes Option-Pricing Model (Details) - Black Scholes - Stock appreciation rights - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Estimated fair value of SAR grant using Black-Scholes options pricing model
Dividend yield	0.00%	0.00%	0.00%
Weighted average risk-free interest rate, Minimum	1.10%	1.10%	1.40%
Weighted average risk-free interest rate, Maximum	1.40%	1.40%	1.60%
Weighted average expected volatility	40.00%	40.00%	40.00%
Expected life in years	6 years 3 months	6 years 3 months	6 years 3 months
Minimum
Estimated fair value of SAR grant using Black-Scholes options pricing model
The weighted average fair value of stock appreciation rights issued (in dollars per share)	$ 2.79	$ 2.79	$ 3.33
Maximum
Estimated fair value of SAR grant using Black-Scholes options pricing model
The weighted average fair value of stock appreciation rights issued (in dollars per share)	$ 3.74	$ 3.74	$ 3.90

Operating Leases - (Details Tex

Operating Leases - (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Leases, Operating [Abstract]
Total rent expense under operating leases	$ 20,013	$ 22,487	$ 19,814

Operating Leases - (Details)

Operating Leases - (Details) $ in Thousands	Dec. 31, 2017USD ($)
Future minimum lease payments under operating leases
2,018	$ 17,032
2,019	14,243
2,020	9,330
2,021	8,900
2,022	2,052
Thereafter	14,953
Total minimum payments	$ 66,510

Derivative Instruments - (Detai

Derivative Instruments - (Details Textual) lb in Millions, gal in Millions	12 Months Ended
	Dec. 31, 2017USD ($)lbgal
Derivative Instruments, Gain (Loss) [Line Items]
Heating oil covered under the open commodity derivative contracts (in gallons) | gal	82.8
Soybean oil covered under the open commodity derivative contracts (in pounds) | lb	78.3
Net position	$ 7,189,000
Commodity contract derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Collateral associated with commodity-based derivatives	$ 8,798,000

Derivative Instruments - (Det85

Derivative Instruments - (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Assets
Gross amounts of commodity derivative contracts recognized at fair value	$ 812	$ 1,272
Cash collateral	8,799	9,366
Total gross amount recognized	9,611	10,638
Gross amounts offset	(8,001)	(3,511)
Net amount reported in the Consolidated Balance Sheets	1,610	7,127
Liabilities
Gross amounts of commodity derivative contracts recognized at fair value	8,001	3,511
Cash collateral	0	0
Total gross amount recognized	8,001	3,511
Gross amounts offset	(8,001)	(3,511)
Net amount reported in the Consolidated Balance Sheets	$ 0	$ 0

Derivative Instruments - Gains

Derivative Instruments - Gains (Losses) included in the Statements of Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cost of goods sold – Biomass-based diesel | Commodity derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax gains (losses) included in the condensed consolidated statement of operations	$ (23,437)	$ (35,386)	$ 35,983

Fair Value Measurement - (Detai

Fair Value Measurement - (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	$ (41,582)	$ (75,907)
Level 1
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	(3,742)	(1,297)
Level 2
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	(3,447)	(28,042)
Level 3
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	(34,393)	(46,568)
Commodity contract derivatives
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	(7,189)	(2,239)
Commodity contract derivatives | Level 1
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	(3,742)	(1,297)
Commodity contract derivatives | Level 2
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	(3,447)	(942)
Commodity contract derivatives | Level 3
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	0	0
Convertible debt conversion liability
Assets (liabilities) measured at fair value
Assets (liabilities), fair value		(27,100)
Convertible debt conversion liability | Level 1
Assets (liabilities) measured at fair value
Assets (liabilities), fair value		0
Convertible debt conversion liability | Level 2
Assets (liabilities) measured at fair value
Assets (liabilities), fair value		(27,100)
Convertible debt conversion liability | Level 3
Assets (liabilities) measured at fair value
Assets (liabilities), fair value		0
Contingent consideration for acquisitions
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	(34,393)	(46,568)
Contingent consideration for acquisitions | Level 1
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	0	0
Contingent consideration for acquisitions | Level 2
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	0	0
Contingent consideration for acquisitions | Level 3
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	$ (34,393)	$ (46,568)

Fair Value Measurement - Recurr

Fair Value Measurement - Recurring Basis (Details) - Contingent consideration for acquisitions - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Liabilities measured at fair value on a recurring basis
Balance at beginning of period	$ 46,568	$ 41,712
Fair value of contingent consideration at measurement date	0	4,500
Change in estimates included in earnings	2,484	7,904
Settlements	(14,659)	(7,548)
Balance at end of period	$ 34,393	$ 46,568

Fair Value Measurement - (Det89

Fair Value Measurement - (Details Textual) (Details)	12 Months Ended
	Dec. 31, 2017
Minimum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Risk adjusted discount rate	5.80%
Maximum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Risk adjusted discount rate	10.00%
LS9, Inc
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Risk adjusted discount rate	8.00%

Fair Value Measurement - Estima

Fair Value Measurement - Estimated Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Asset (Liability) Carrying Amount
Financial Liabilities:
Debt and lines of credit	$ (294,085)	$ (270,735)
Estimated Fair Value
Financial Liabilities:
Debt and lines of credit	$ (273,983)	$ (264,267)

Net Income (Loss) Per Share (De

Net Income (Loss) Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	20,296,470	18,571,555	12,997,374
Stock appreciation rights
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	622,633	2,422,716	2,072,130
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	0	43,513	87,026
2019 Convertible notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	5,567,112	7,895,675	10,838,218
2036 Convertible notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	14,106,725	8,209,651	0

Net Income (Loss) Per Share - E

Net Income (Loss) Per Share - EPS Reconciliation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Net income (loss) attributable to the Company's common stockholders - Basic									$ (79,079)	$ 43,453	$ (151,392)
Plus (less): effect of participating securities									0	874	0
Net income (loss) attributable to common stockholders									(79,079)	44,327	(151,392)
Less: effect of participating securities									0	(874)	0
Net income (loss) attributable to the Company's common stockholders - Diluted									$ (79,079)	$ 43,453	$ (151,392)
Weighted-average shares outstanding - Basic (in shares)									38,731,015	40,897,549	43,958,803
Adjustment to reflect stock appreciation right conversions (in shares)									0	5,311	0
Weighted-average shares outstanding - Diluted (in shares)									38,731,015	40,902,860	43,958,803
Net income (loss) per share attributable to common stockholders - diluted (in dollars per share)	$ (0.44)	$ (0.29)	$ (0.90)	$ (0.41)	$ 0.51	$ 0.59	$ 0.18	$ (0.14)	$ (2.04)	$ 1.06	$ (3.44)

Reportable Segments and Geogr93

Reportable Segments and Geographic Information - (Details Textual) - segment	3 Months Ended
	Dec. 31, 2015	Sep. 30, 2015
Segment Reporting [Abstract]
Number of Reportable Segments	3	2

Reportable Segments and Geogr94

Reportable Segments and Geographic Information - (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment for the results of operations
Net sales	$ 2,158,243	$ 2,041,232	$ 1,387,344
Income (loss) before income taxes	(109,569)	48,981	(160,411)
Depreciation and amortization expense, net	36,936	32,877	25,876
Cash paid for purchases of property, plant and equipment	67,572	60,705	64,477
Goodwill	16,080	16,080
Assets	1,005,596	1,136,603
Corporate and other
Segment for the results of operations
Net sales	212,557	106,572	68,984
Income (loss) before income taxes	(29,217)	984	(13,854)
Depreciation and amortization expense, net	2,167	1,696	1,362
Cash paid for purchases of property, plant and equipment	2,998	2,549	2,436
Assets	386,590	299,825
Operating Segments | Biomass-based Diesel
Segment for the results of operations
Net sales	2,039,982	1,952,361	1,326,452
Income (loss) before income taxes	(63,925)	64,814	(100,152)
Depreciation and amortization expense, net	31,011	29,018	22,799
Cash paid for purchases of property, plant and equipment	60,734	52,952	59,859
Goodwill	0	0
Assets	898,180	1,026,349
Operating Segments | Biomass-based Diesel | REG Germany
Segment for the results of operations
Net sales	171,175	171,358	145,039
Income (loss) before income taxes	(7,544)	5,007	(1,643)
Depreciation and amortization expense, net	2,990	2,849	3,259
Cash paid for purchases of property, plant and equipment	3,241	1,353	1,816
Assets	55,761	51,822
Operating Segments | Services
Segment for the results of operations
Net sales	103,215	87,014	102,731
Income (loss) before income taxes	2,899	2,970	6,323
Depreciation and amortization expense, net	1,092	613	302
Cash paid for purchases of property, plant and equipment	3,826	4,731	1,510
Goodwill	16,080	16,080
Assets	55,581	53,823
Operating Segments | Renewable Chemicals
Segment for the results of operations
Net sales	4,531	2,065	0
Income (loss) before income taxes	(19,326)	(19,787)	(52,728)
Depreciation and amortization expense, net	2,666	1,550	1,413
Cash paid for purchases of property, plant and equipment	14	473	672
Goodwill	0	0
Assets	21,168	22,883
Intersegment revenues
Segment for the results of operations
Net sales	(202,042)	(106,780)	$ (110,823)
Intersegment eliminations
Segment for the results of operations
Assets	$ (355,923)	$ (266,277)

Reportable Segments and Geogr95

Reportable Segments and Geographic Information - Geographic Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 577,264	$ 626,983	$ 535,103	$ 418,893	$ 560,421	$ 624,640	$ 558,301	$ 297,870	$ 2,158,243	$ 2,041,232	$ 1,387,344
Long-lived assets	587,397				599,474				587,397	599,474
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									1,961,303	1,869,874	1,242,305
Long-lived assets	566,028				580,868				566,028	580,868
Germany
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									171,175	171,358	145,039
Long-lived assets	20,689				18,472				20,689	18,472
Other Foreign
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									25,765	0	0
Long-lived assets	680				134				680	134
Total Foreign
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									196,940	171,358	$ 145,039
Long-lived assets	$ 21,369				$ 18,606				$ 21,369	$ 18,606

Commitments and Contingencies96

Commitments and Contingencies (Details) $ in Thousands	Dec. 31, 2017USD ($)
Commitments and Contingencies Disclosure [Abstract]
2,018	$ 3,784
2,019	3,748
2,020	3,297
2,021	2,976
2,022	2,976
Thereafter	6,798
Total	$ 23,579

Subsequent Events (Details)

Subsequent Events (Details) - Subsequent Event $ in Millions	6 Months Ended
	Jun. 30, 2018USD ($)
Minimum
Subsequent Event [Line Items]
2017 BTC net benefit	$ 210
Maximum
Subsequent Event [Line Items]
2017 BTC net benefit	$ 220

Supplemental Quarterly Inform98

Supplemental Quarterly Information (Unaudited) - (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Significant items for the results of operations on a quarterly basis
Revenues	$ 577,264	$ 626,983	$ 535,103	$ 418,893	$ 560,421	$ 624,640	$ 558,301	$ 297,870	$ 2,158,243	$ 2,041,232	$ 1,387,344
Gross profit (loss)	20,049	14,795	31,454	17,283	81,920	47,350	24,862	17,384	83,581	171,516	110,543
Selling, general, and administrative expenses including research and development expense	25,379	29,639	25,993	26,505	31,864	25,604	25,277	23,703
Impairment of property, plant and equipment	48,532	0	1,341	0	17,893	0	0	0	49,873	17,893	0
Net income (loss) from operations	(53,862)	(14,844)	4,120	(9,222)	32,163	21,746	(415)	(6,319)	(73,808)	47,175	(154,733)
Other income (expense), net	3,469	3,356	(36,969)	(5,617)	(6,343)	558	7,432	159	(35,761)	1,806	(5,678)
Net income (loss) attributable to the Company	$ (16,983)	$ (11,373)	$ (34,809)	$ (15,914)	$ 20,197	$ 23,442	$ 7,606	$ (6,918)	$ (79,079)	$ 44,327	$ (151,392)
Net income (loss) per share attributable to common stockholders - basic (in dollars per share)	$ (0.44)	$ (0.29)	$ (0.90)	$ (0.41)	$ 0.51	$ 0.59	$ 0.18	$ (0.16)	$ (2.04)	$ 1.06	$ (3.44)
Net income (loss) per share attributable to common stockholders - diluted (in dollars per share)	$ (0.44)	$ (0.29)	$ (0.90)	$ (0.41)	$ 0.51	$ 0.59	$ 0.18	$ (0.14)	$ (2.04)	$ 1.06	$ (3.44)

Supplemental Quarterly Inform99

Supplemental Quarterly Information (Unaudited) - (Details Textual) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended			21 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016
Impairment of property, plant and equipment, net	$ 48,532	$ 0	$ 1,341	$ 0	$ 17,893	$ 0	$ 0	$ 0	$ 49,873	$ 17,893	$ 0
Insurance recoveries	5,000	3,000							8,000			$ 19,037
Gain on involuntary conversion	4,387	$ 942							5,329	9,894	$ 0	$ 8,010
New Orleans
Impairment of property, plant and equipment, net	$ 44,649								$ 44,649
Emporia
Impairment of property, plant and equipment, net										$ 15,593