Segment Information (Details) $ in Millions	3 Months Ended	9 Months Ended	10 Months Ended
Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) segment	Sep. 30, 2017 USD ($)	Oct. 16, 2017 segment
Segment Reporting Information [Line Items]
Number of Operating Segments \| segment			3		2
REVENUE	$ 192.9	$ 291.6	$ 645.4	$ 986.1
Operating expenses:
Direct operating costs (excluding items below)	182.3	168.7	516.0	508.8
Depreciation and amortization	99.0	103.4	294.3	304.0
Selling, general and administrative	26.6	24.9	77.4	71.3
Other operating items	1.5	2.8	5.0	9.3
Equity in earnings of unconsolidated subsidiary	3.1	0.0	3.4	0.0
INCOME (LOSS) FROM OPERATIONS	(113.4)	(8.2)	(243.9)	92.7
Deepwater Segment [Member]
Segment Reporting Information [Line Items]
REVENUE	13.9	88.4	131.8	371.8
Jack-ups [Member]
Segment Reporting Information [Line Items]
REVENUE	170.0	203.2	486.7	614.3
Operating Segments [Member]
Segment Reporting Information [Line Items]
REVENUE	282.1	291.6	863.7	986.1
Operating expenses:
Direct operating costs (excluding items below)	233.5	168.7	636.5	508.8
Depreciation and amortization	116.0	103.4	344.7	304.0
Selling, general and administrative	33.4	24.9	97.4	71.3
Other operating items	0.5	2.8	5.0	9.3
Equity in earnings of unconsolidated subsidiary	0.0		0.0
INCOME (LOSS) FROM OPERATIONS	(101.3)	(8.2)	(219.9)	92.7
Operating Segments [Member] \| Deepwater Segment [Member]
Segment Reporting Information [Line Items]
REVENUE	13.9	88.4	131.8	371.8
Operating expenses:
Direct operating costs (excluding items below)	48.4	33.2	118.2	117.1
Depreciation and amortization	27.3	27.4	81.2	84.1
Selling, general and administrative	0.0	0.0	0.0	0.0
Other operating items	0.0	0.0	0.0	0.0
Equity in earnings of unconsolidated subsidiary	0.0		0.0
INCOME (LOSS) FROM OPERATIONS	(61.8)	27.8	(67.6)	170.6
Operating Segments [Member] \| Jack-ups [Member]
Segment Reporting Information [Line Items]
REVENUE	170.0	203.2	486.7	614.3
Operating expenses:
Direct operating costs (excluding items below)	133.9	135.5	397.8	391.7
Depreciation and amortization	71.1	75.3	211.3	217.8
Selling, general and administrative	0.0	0.0	0.0	0.0
Other operating items	1.5	2.7	5.0	9.3
Equity in earnings of unconsolidated subsidiary	0.0		0.0
INCOME (LOSS) FROM OPERATIONS	(36.5)	(10.3)	(127.4)	(4.5)
Operating Segments [Member] \| ARO Segment [Member]
Segment Reporting Information [Line Items]
REVENUE	89.2	0.0	218.3	0.0
Operating expenses:
Direct operating costs (excluding items below)	51.2	0.0	120.5	0.0
Depreciation and amortization	17.0	0.0	50.4	0.0
Selling, general and administrative	6.8	0.0	20.0	0.0
Other operating items	(1.0)	0.0	0.0	0.0
Equity in earnings of unconsolidated subsidiary	0.0		0.0
INCOME (LOSS) FROM OPERATIONS	15.2	0.0	27.4	0.0
Unallocated and other
Segment Reporting Information [Line Items]
REVENUE	9.0	0.0	26.9	0.0
Operating expenses:
Direct operating costs (excluding items below)	0.0	0.0	0.0	0.0
Depreciation and amortization	0.6	0.7	1.8	2.1
Selling, general and administrative	26.6	24.9	77.4	71.3
Other operating items	0.0	0.1	0.0	0.0
Equity in earnings of unconsolidated subsidiary	0.0		0.0
INCOME (LOSS) FROM OPERATIONS	(18.2)	(25.7)	(52.3)	(73.4)
Eliminations and adjustments
Segment Reporting Information [Line Items]
REVENUE	(89.2)	0.0	(218.3)	0.0
Operating expenses:
Direct operating costs (excluding items below)	(51.2)	0.0	(120.5)	0.0
Depreciation and amortization	(17.0)	0.0	(50.4)	0.0
Selling, general and administrative	(6.8)	0.0	(20.0)	0.0
Other operating items	1.0	0.0	0.0	0.0
Equity in earnings of unconsolidated subsidiary	3.1		3.4
INCOME (LOSS) FROM OPERATIONS	(12.1)	0.0	(24.0)	0.0
Parent Company [Member] \| Saudi Arabia Joint Venture [Member]
Operating expenses:
Equity in earnings of unconsolidated subsidiary	$ 3.1		$ 3.4
Equity Method Investment, Ownership Percentage	50.00%		50.00%
Saudi Arabia \| Jack-ups [Member]
Segment Reporting Information [Line Items]
REVENUE	$ 88.8	102.7	$ 270.8	290.2
Saudi Arabia \| Unallocated and other
Segment Reporting Information [Line Items]
REVENUE	9.0	0.0	26.9	0.0
Norway \| Jack-ups [Member]
Segment Reporting Information [Line Items]
REVENUE	2.3	45.8	65.7	140.9
Trinidad \| Jack-ups [Member]
Segment Reporting Information [Line Items]
REVENUE	39.8	30.3	83.1	106.3
United Kingdom \| Jack-ups [Member]
Segment Reporting Information [Line Items]
REVENUE	28.8	12.7	50.7	41.9
United States \| Deepwater Segment [Member]
Segment Reporting Information [Line Items]
REVENUE	13.9	88.4	131.8	369.4
United States \| Jack-ups [Member]
Segment Reporting Information [Line Items]
REVENUE	10.3	11.7	16.4	34.9
Other \| Deepwater Segment [Member]
Segment Reporting Information [Line Items]
REVENUE	0.0	0.0	0.0	2.4
Other \| Jack-ups [Member]
Segment Reporting Information [Line Items]
REVENUE	$ 0.0	$ 0.0	$ 0.0	$ 0.1
Saudi Aramco [Member] \| Saudi Arabia Joint Venture [Member]
Operating expenses:
Equity Method Investment, Ownership Percentage	50.00%		50.00%

Amount of expense for allocation of cost of tangible and intangible assets over their useful lives, and reduction in quantity of natural resource due to consumption directly used in production of good and rendering of service.

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