Property and Equipment (Schedule of estimated useful lives and costs of asset classes) (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 1,118,215	$ 1,093,635
Drilling Rigs [Member] | Drilling Services [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 590,148	594,743
Drilling Rigs [Member] | Drilling Services [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Drilling Rigs [Member] | Drilling Services [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	25 years
Well Service Rigs [Member] | Production Services [Member] | Well Servicing [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 252,589	244,747
Well Service Rigs [Member] | Production Services [Member] | Well Servicing [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Well Service Rigs [Member] | Production Services [Member] | Well Servicing [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	20 years
Wireline Units [Member] | Production Services [Member] | Wireline Services [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 144,171	142,224
Wireline Units [Member] | Production Services [Member] | Wireline Services [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	1 year
Wireline Units [Member] | Production Services [Member] | Wireline Services [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	10 years
Coiled Tubing Units [Member] | Production Services [Member] | Coiled Tubing Services [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 25,689	18,141
Coiled Tubing Units [Member] | Production Services [Member] | Coiled Tubing Services [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	1 year
Coiled Tubing Units [Member] | Production Services [Member] | Coiled Tubing Services [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	7 years
Vehicles [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 50,317	47,932
Vehicles [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Vehicles [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	10 years
Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 11,606	12,717
Office Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Office Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	10 years
Building and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 23,610	24,013
Building and Building Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Building and Building Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	40 years
Property and equipment not yet placed in service [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 17,718	6,751
Property and equipment not yet placed in service [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	0 years
Property and equipment not yet placed in service [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	0 years
Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 2,367	$ 2,367
Land [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	0 years
Land [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	0 years