Income Taxes (Deferred Assets and Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred tax assets:
Allowance for uncollectible accounts	$ 1,096	$ 897
Accrued assets and other	27,537	5,292
Valuation allowances	(3,736)	(2,021)
Total current deferred tax assets	24,897us-gaap_DeferredTaxAssetsNetCurrent	4,168us-gaap_DeferredTaxAssetsNetCurrent
Share-based compensation	7,719	7,635
Interest on unrecognized tax benefits	245	230
Accrued liabilities and other	3,931	3,629
Medical malpractice	16,240	0
Operating and capital loss carryforwards	22,709	9,185
Valuation allowances	(13,721)	(7,665)
Total non-current deferred tax assets	37,123us-gaap_DeferredTaxAssetsNetNoncurrent	13,014us-gaap_DeferredTaxAssetsNetNoncurrent
Total deferred tax assets	62,020us-gaap_DeferredTaxAssetsNet	17,182us-gaap_DeferredTaxAssetsNet
Deferred tax liabilities:
Prepaid expenses	2,435us-gaap_DeferredTaxLiabilitiesOther	1,071us-gaap_DeferredTaxLiabilitiesOther
Property and equipment, principally due to differences in depreciation	15,235	4,137
Goodwill, intangible assets and other, principally due to differences in amortization	655,368	184,897
Total deferred tax liabilities	673,038us-gaap_DeferredIncomeTaxLiabilities	190,105us-gaap_DeferredIncomeTaxLiabilities
Net deferred tax liabilities	$ 611,018us-gaap_DeferredTaxLiabilities	$ 172,923us-gaap_DeferredTaxLiabilities

The sum of the tax effects as of the balance sheet date of the amount of excesses of tax deductions over gross income in a year which cannot be used on the tax returns in the current year but can be carried forward to reduce taxable income or income taxes payable in a future year, for which there must be sufficient tax-basis income to utilize a portion or all of the carryforward amount to realize the deferred tax asset as well as the amount of future tax deductions arising from capital losses in excess of statutory limitations in historical filings, and which can only be utilized if sufficient tax-basis income is generated in future periods and providing tax laws continue to allow such utilization.

No definition available.