Credit Agreement - Schedule of U.S. Credit Agreement (Parenthetical) (Detail) - Credit Agreement [Member] - USD ($)		Dec. 31, 2015	Dec. 31, 2014
Line Of Credit Facility [Line Items]
Outstanding letters of credit	[1],[2]	$ 10,446,000	$ 11,563,000
Letter Of Credit | BMO Harris Bank N.A. (“BMO Harris”) [Member]
Line Of Credit Facility [Line Items]
Letter of credit collateralized of restricted cash		10,400,000	11,600,000
Outstanding letters of credit		1,400,000	1,300,000
Letters of credit sub limited		$ 60,000,000	$ 95,000,000

[1] As of December 31, 2015 and 2014, outstanding letters of credit not related to the Credit Agreement totaled $1.4 million and $1.3 million, respectively, which amount is fully collateralized with restricted cash, which is in addition to the $10.4 million and $11.6 million, respectively, referenced in the preceding note.

[2] Represents letters of credit which are fully collateralized with $10.4 million and $11.6 million of restricted cash as of December 31, 2015 and 2014, respectively.