Geographic Information for Long-Lived Assets and Revenues in United States and other Countries (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Long-lived assets:
Long-lived assets	$ 489,403				$ 440,069				$ 489,403	$ 440,069	$ 418,502
Revenues:
Revenues	164,520	201,477	153,744	147,657	153,622	151,134	177,614	163,166	667,398	645,536	625,705
UNITED STATES
Long-lived assets:
Long-lived assets	454,031				403,534				454,031	403,534	377,667
Revenues:
Revenues									529,603	500,106	495,777
CANADA
Revenues:
Revenues									43,329	30,929	34,001
Other International
Revenues:
Revenues									94,466	114,501	95,927
International, Primarily China and Russia
Long-lived assets:
Long-lived assets	$ 35,372				$ 36,535				$ 35,372	$ 36,535	$ 40,835