Revenue from Contracts with Customers (Tables)

12 Months Ended

Dec. 31, 2018

Revenue from Contracts with Customer [Abstract]

Schedule of Allowance for Doubtful Accounts [Table Text Block]

The changes in our allowance for doubtful accounts consist of the following (amounts in thousands):

	Year ended December 31,
	2018			2017			2016
Balance at beginning of year	$	1,224		$	1,678		$	2,254
Increase (decrease) in allowance charged to expense	271			(197		)	404
Accounts charged against the allowance	(72		)	(257		)	(980		)
Balance at end of year	$	1,423		$	1,224		$	1,678

Schedule of Unbilled Receivables [Table Text Block]

Our unbilled receivables as of December 31, 2018 and December 31, 2017were as follows (amounts in thousands):

	December 31, 2018		December 31, 2017
Daywork drilling contracts in progress	$	24,365	$	15,254
Production services	457		775
	$	24,822	$	16,029

Schedule of Deferred Revenues and Costs [Table Text Block]

Our current and noncurrent deferred revenues and costs as of December 31, 2018 and January 1, 2018were as follows (amounts in thousands):

	December 31, 2018		January 1, 2018
Current deferred revenues	$	1,722	$	1,287
Current deferred costs	1,543		1,072
Noncurrent deferred revenues	$	437	$	564
Noncurrent deferred costs	679		1,177

Amortization of Deferred Revenue and Costs [Table Text Block]

Amortization of deferred revenues and costs during the years ended December 31, 2018, 2017 and 2016 were as follows (amounts in thousands):

	Year ended December 31,
	2018		2017		2016
Amortization of deferred revenues	$	2,961	$	2,400	$	1,566
Amortization of deferred costs	2,855		4,953		2,813