Revenue (Tables)

3 Months Ended

Mar. 31, 2020

Revenue from Contract with Customer [Abstract]

Schedule of Sales by Major Source

The following table disaggregates our sales by major source for the three months ended March 31, 2020 and 2019 (in thousands):

	Three Months Ended   March 31, 2020						Three Months Ended   March 31, 2019
Category	Oil & Gas Proppants		Industrial & Specialty Products		Total Sales		Oil & Gas Proppants		Industrial & Specialty Products		Total Sales
Product	$	108,277	$	113,884	$	222,161	$	178,587	$	118,273	$	296,860
Service	47,438		—		47,438		81,890		—		81,890
Total Sales	$	155,715	$	113,884	$	269,599	$	260,477	$	118,273	$	378,750

Schedule of Changes in Contract Assets and Liabilities

The following tables reflect the changes in our contract assets, which we classify as unbilled receivables and our contract liabilities, which we classify as deferred revenues, for the three months ended March 31, 2020 and 2019 (in thousands):

	Unbilled Receivables
	March 31, 2020			March 31, 2019
Beginning Balance	$	144		$	90
Reclassifications to billed receivables	(144		)	(90		)
Revenues recognized in excess of period billings	108			1,641
Ending Balance	$	108		$	1,641

	Deferred Revenue
	March 31, 2020			March 31, 2019
Beginning Balance	$	50,634		$	113,319
Revenues recognized from balances held at the beginning of the period	(2,525		)	(6,704		)
Revenues deferred from period collections on unfulfilled performance obligations	—			10,025
Revenues recognized from period collections	—			(872		)
Ending Balance	$	48,109		$	115,768

Schedule of Revenue Related to Foreign Operations

The following table includes information related to our foreign operations for the three months ended March 31, 2020 and 2019:

	March 31, 2020		March 31, 2019
Total Sales	$	21,605	$	15,300
Pre-tax income	$	4,213	$	900
Net income	$	3,328	$	800
Consolidated Assets	$	29,705	$	10,100

Schedule of Consolidated Assets Related to Foreign Operations

The following table includes information related to our foreign operations for the three months ended March 31, 2020 and 2019:

	March 31, 2020		March 31, 2019
Total Sales	$	21,605	$	15,300
Pre-tax income	$	4,213	$	900
Net income	$	3,328	$	800
Consolidated Assets	$	29,705	$	10,100