Industry Segments (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Corporate Overhead Footnote
General and administrative expense	$ 9,912	$ 10,368
Depreciation and amortization	869	685
Interest expense	4,191	4,354
Other general corporate (income) expense, net	814	234
Total	$ 15,786	$ 15,641