Summary of Assets by Segment (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Feb. 25, 2017	Dec. 31, 2016
ASSETS
Total assets	$ 19,388,264		$ 18,741,257
U.S. dialysis and related lab services
ASSETS
Total assets	11,744,695	$ 338,963	11,099,137
DMG
ASSETS
Total assets	6,209,369		6,213,091
Ancillary services and strategic initiatives
ASSETS
Total assets	$ 1,434,200		$ 1,429,029