Summary of Activity for Each of Company's Other Investments (Detail) - USD ($) $ in Thousands		1 Months Ended	3 Months Ended		9 Months Ended
		Dec. 31, 2013	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Schedule of Equity Method Investments [Line Items]
Investments, beginning balance					$ 98,317
Cash distributions	[1]		$ (2,402)	$ (1,391)	(17,321)	$ (9,660)
Equity in income			10,902	12,390	26,767	24,597
Equity in other comprehensive income			(11)	$ (7)	92	$ (183)
Investments, ending balance			112,878		112,878
AC JV, LLC
Schedule of Equity Method Investments [Line Items]
Cash contributions		$ 268
Other Affiliates
Schedule of Equity Method Investments [Line Items]
Investments, beginning balance					98,317
Cash contributions					1,177
Cash distributions					(5,212)
Equity in income					18,669
Equity in other comprehensive income					92
Other					(165)
Investments, ending balance			112,878		112,878
Other Affiliates | Digital Cinema Implementation Partners
Schedule of Equity Method Investments [Line Items]
Investments, beginning balance					87,819
Cash contributions					1,109
Cash distributions					(5,212)
Equity in income					16,820
Equity in other comprehensive income					92
Other					0
Investments, ending balance			100,628		100,628
Other Affiliates | AC JV, LLC
Schedule of Equity Method Investments [Line Items]
Investments, beginning balance					5,980
Cash contributions					0
Cash distributions					0
Equity in income					996
Equity in other comprehensive income					0
Other					0
Investments, ending balance			6,976		6,976
Other Affiliates | Digital Cinema Distribution Coalition
Schedule of Equity Method Investments [Line Items]
Investments, beginning balance					2,750
Cash contributions					0
Cash distributions					0
Equity in income					853
Equity in other comprehensive income					0
Other					0
Investments, ending balance			3,603		3,603
Other Affiliates | Other Investments
Schedule of Equity Method Investments [Line Items]
Investments, beginning balance					1,768
Cash contributions					68
Cash distributions					0
Equity in income					0
Equity in other comprehensive income					0
Other					(165)
Investments, ending balance			$ 1,671		$ 1,671

[1] Includes cash distributions received from equity investees that were recorded as a reduction of the respective investment balances (see Notes 6 and 7). These distributions are reported entirely within the U.S. operating segment.