Consolidated Statements of Financial Position (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Statement Of Financial Position [Abstract]
Accounts receivable, allowances	$ 27,261	$ 24,852
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, authorized	5,000,000	5,000,000
Preferred stock, issued	0	0
Preferred stock, outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, authorized	260,000,000	260,000,000
Common stock, issued	137,466,421	139,438,603
Common stock, outstanding	137,466,421	139,438,603