CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Statement Of Financial Position [Abstract]
Accounts receivable, reserves (in dollars)	$ 2,155	$ 2,625
Preferred shares, no par value
Preferred shares, authorized	5,000,000	5,000,000
Preferred shares, issued	0	0
Common shares, no par value
Common shares, authorized	60,000,000	60,000,000
Common shares, issued	28,851,000	28,803,000
Common shares, outstanding	28,244,000	28,483,000
Common shares held in treasury, shares	607,000	320,000