Supplemental Statements of Cash Flows Disclosures Supplemental Statements of Cash Flows Disclosures (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Supplemental Statements of Cash Flow Disclosures [Abstract]
Interest on long-term debt and borrowing under the revolving credit facility	$ 50,189	$ 48,797	$ 47,783
Income taxes paid (refund), net	5,031	(6,260)	7,343
Grants of restricted shares of common stock	2,411	3,268	2,098
Issuance of performance shares	1,193	628	663
Acquisition of treasury stock for options exercised	$ 0	$ 500	$ 0