Income Taxes - Components of Income from Continuing Operations before Income Taxes and Noncontrolling Shareholders' Interests (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income From Continuing Operations Before Income Taxes And Noncontrolling Shareholders Interests [Line Items]
Income from continuing operations before income taxes and noncontrolling shareholders' interests	$ 99,982	$ 74,236	$ 106,005	$ 86,870	$ 95,922	$ 78,173	$ 95,294	$ 64,639	$ 367,093	$ 334,028	$ 348,519
United States
Income From Continuing Operations Before Income Taxes And Noncontrolling Shareholders Interests [Line Items]
Income from continuing operations before income taxes and noncontrolling shareholders' interests									319,156	314,263	165,888
Foreign
Income From Continuing Operations Before Income Taxes And Noncontrolling Shareholders Interests [Line Items]
Income from continuing operations before income taxes and noncontrolling shareholders' interests									$ 47,937	$ 19,765	$ 182,631