Long-Term Debt And Capital Lease Obligations (Components Of Long-Term Debt And Capital Lease Obligations) (Details) (USD $)	3 Months Ended
	Mar. 31, 2012		Dec. 31, 2011
Long-Term Debt And Capital Lease Obligations [Line Items]
Notes payable to former shareholders of acquired business	$ 29,349,000		$ 29,445,000
Less current portion	154,619,000		153,312,000
Total capital lease obligations	63,000		94,000
Less current portion	39,000		70,000
Capital lease obligations, net of current portion	24,000		24,000
Long-term debt, net of current portion	643,306,000		643,555,000
Total debt	797,925,000		796,867,000
Long-term debt and capital lease obligations, net of current portion	643,330,000		643,579,000
Principal amount of notes	816,000,000		815,000,000
7 3/4 % Senior Notes Due 2016 [Member]
Long-Term Debt And Capital Lease Obligations [Line Items]
Senior notes	220,306,000	[1]	220,555,000	[1]
Interest percentage	7.75%
Debt maturity period	2016
6 3/4 % Senior Notes Due 2020 [Member]
Long-Term Debt And Capital Lease Obligations [Line Items]
Senior notes	400,000,000		400,000,000
Interest percentage	6.75%
Debt maturity period	2020
3 3/4% Senior Subordinated Convertible Notes Due 2012 [Member]
Long-Term Debt And Capital Lease Obligations [Line Items]
Senior subordinated convertible notes	148,270,000	[2]	146,867,000	[2]
Interest percentage	3.75%
Debt maturity period	2012
Principal amount of notes	149,900,000
Principal amount of convertible notes, discount amount	1,700,000		3,100,000
Senior Notes [Member]
Long-Term Debt And Capital Lease Obligations [Line Items]
Principal amount of notes	215,000,000
Senior notes, premium amount	$ 5,300,000		$ 5,600,000

[1] Balance includes $215.0 million principal amount of 2016 Notes including a premium of $5.3 million at March 31, 2012 and $5.6 million at December 31, 2011.

[2] Balance includes $149.9 million principal amount of Convertible Notes net of discount of $1.7 million at March 31, 2012 and $3.1 million at December 31, 2011.