Use of Estimates	3 Months Ended
Mar. 31, 2013
Use Of Estimates [Abstract]
Use of Estimates	(2) Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. The determination of contractual and bad debt allowances constitutes a significant estimate. Some of the factors considered by management in determining the amount of such allowances are the historical trends of the centers' cash collections and contractual and bad debt write-offs, accounts receivable agings, established fee schedules, contracts with payors and procedure statistics. Accordingly, net accounts receivable at March 31, 2013 and December 31, 2012 reflect allowances for contractual adjustments of $281,290,000 and $216,363,000, respectively, and allowances for bad debt expense of $24,276,000 and $22,379,000, respectively. The increase in the allowance for contractual adjustments as of March 31, 2013 is primarily the result of the centers acquired at the end of 2012 and increases in gross fee schedules at certain of the Company's centers. For the three months ended March 31, 2013 and 2012, bad debt expense was approximately $5,914,000 and $5,183,000, respectively, and is included in other operating expenses.

Use of Estimates

3 Months Ended

Mar. 31, 2013

(2) Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

The determination of contractual and bad debt allowances constitutes a significant estimate. Some of the factors considered by management in determining the amount of such allowances are the historical trends of the centers' cash collections and contractual and bad debt write-offs, accounts receivable agings, established fee schedules, contracts with payors and procedure statistics. Accordingly, net accounts receivable at March 31, 2013 and December 31, 2012 reflect allowances for contractual adjustments of $281,290,000 and $216,363,000, respectively, and allowances for bad debt expense of $24,276,000 and $22,379,000, respectively. The increase in the allowance for contractual adjustments as of March 31, 2013 is primarily the result of the centers acquired at the end of 2012 and increases in gross fee schedules at certain of the Company's centers. For the three months ended March 31, 2013 and 2012, bad debt expense was approximately $5,914,000 and $5,183,000, respectively, and is included in other operating expenses.