Nature of Operations (Details)	3 Months Ended
	Mar. 31, 2018 segment county country item
Nature of Operations
The minimum number of countries in whcih the entity operates | country	25
Actively marketed rigs for land based drilling operations	407
Number of countries company has actively marketed rigs for land based drilling operations | county	20
Actively marketed rigs for offshore based drilling operations	38
Number of reportable segments | segment	5