Components Of Long-Term Debt And Capital Lease Obligations (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Long-Term Debt And Capital Lease Obligations [Line Items]
Revolving line of credit	$ 75,000
Notes payable to former shareholders of acquired business	23,000		29,445
Total debt	717,797		796,867
Less current portion	81,000		153,312
Long-term debt, net of current portion	636,797		643,555
Total capital lease obligations	45		94
Less current portion	21		70
Capital lease obligations, net of current portion	24		24
Long-term debt and capital lease obligations, net of current portion	636,821		643,579
7 3/4 % Senior Notes Due 2016
Long-Term Debt And Capital Lease Obligations [Line Items]
Senior notes	219,797	[1]	220,555	[1]
6 3/4 % Senior Notes Due 2020
Long-Term Debt And Capital Lease Obligations [Line Items]
Senior notes	400,000		400,000
3 3/4% Senior Subordinated Convertible Notes Due 2012
Long-Term Debt And Capital Lease Obligations [Line Items]
Senior subordinated convertible notes			$ 146,867	[2]

[1] Balance includes $215.0 million principal amount of 2016 Notes and a premium of $4.8 million at September 30, 2012 and $5.6 million at December 31, 2011.

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