Components of Selected Balance Sheet Accounts (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Other current assets:
Tubular inventory and well materials	$ 3,792		$ 4,061
Prepaid expenses	1,778		1,064
Other Assets, Current	5,570		5,125
Other assets:
Deferred issuance costs of the Revolver	4,179		2,437
Operating Lease, Right-of-Use Asset	2,901	$ 2,500	0
Other	67		44
Other assets	7,147		2,481
Accounts payable and accrued liabilities:
Trade accounts payable	33,036		16,507
Drilling costs	25,105		22,434
Royalties and revenue – related	43,354		51,212
Production, ad valorem and other taxes	7,562		2,418
Compensation – related	5,011		4,489
Interest	675		670
Operating Lease, Liability, Current	858		0
Other	3,374		5,970
Accounts payable and accrued liabilities	118,975		103,700
Other liabilities:
Asset retirement obligations	4,784		4,314
Operating Lease, Liability, Noncurrent	2,389		0
Defined benefit pension obligations	777		857
Postretirement health care benefit obligations	409		362
Other liabilities	$ 8,359		$ 5,533