CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Statement of Financial Position [Abstract]
Accounts receivable, allowance for doubtful accounts (in dollars)	$ 8,398	$ 8,654
Preferred shares, authorized	5,000,000	5,000,000
Preferred shares, issued	0	0
Preferred shares, outstanding	0	0
Common shares, authorized	240,000,000	240,000,000
Common shares, issued	98,581,434	98,581,434
Common shares, outstanding	81,010,084	82,944,817
Treasury shares	17,571,350	15,636,617