Selected Segment Financial Data, Revenues and Long lived Assets (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Revenues
Revenues	$ 231,462	$ 226,066
Long lived assets
Long lived assets	1,404,499		$ 1,416,825
United States [Member]
Revenues
Revenues	135,002	133,365
Long lived assets
Long lived assets	783,950		752,442
United Kingdom [Member]
Long lived assets
Long lived assets	202,915		204,193
Other [Member]
Revenues
Revenues	96,460	$ 92,701
Long lived assets
Long lived assets	$ 417,634		$ 460,190