Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating activities
Net income	$ 220,645	$ 125,270	$ 135,996
Adjustments to reconcile net income to net cash provided by operating activities:
Distributions from unconsolidated subsidiaries	20,006	20,476	13,969
Depreciation and amortization	160,011	145,311	104,981
Provision for bad debts	79,491	69,093	59,372
Equity in earnings of unconsolidated subsidiaries	(21,054)	(19,943)	(16,811)
Loss on extinguishment of debt	6,527	11,626	0
Gain on sale of assets and businesses	(10,349)	(46,488)	(1,098)
Gain on sale of equity investment	0	(2,779)	(29,647)
Impairment of equity investment	0	5,339	0
Stock compensation expense	19,284	17,413	14,985
Amortization of debt discount, premium and issuance costs	11,130	15,656	9,543
Deferred income taxes	(72,324)	(12,591)	(2,058)
Changes in operating assets and liabilities, net of effects of business combinations:
Accounts receivable	(197,191)	(39,320)	(92,572)
Other current assets	1,597	17,450	(2,503)
Other assets	(886)	9,290	4,713
Accounts payable	3,903	(15,492)	2,345
Accrued expenses	17,341	46,292	7,200
Net cash provided by operating activities	238,131	346,603	208,415
Investing activities
Business combinations, net of cash acquired	(27,390)	(472,206)	(1,061,628)
Purchases of property and equipment	(233,243)	(161,633)	(182,642)
Investment in businesses	(12,682)	(4,723)	(2,347)
Proceeds from sale of assets and businesses	80,350	80,463	1,767
Proceeds from sale of equity investment	0	3,779	33,096
Net cash used in investing activities	(192,965)	(554,320)	(1,211,754)
Financing activities
Borrowings on revolving facilities	970,000	575,000	1,135,000
Payments on revolving facilities	(960,000)	(655,000)	(895,000)
Proceeds from term loans	1,139,487	795,344	623,575
Payments on term loans	(1,179,442)	(438,034)	(29,134)
Revolving facility debt issuance costs	(4,392)	0	0
Borrowings of other debt	46,621	27,721	13,374
Principal payments on other debt	(20,647)	(21,401)	(18,136)
Dividends paid to common stockholders	0	0	(13,129)
Repurchase of common stock	(4,753)	(2,929)	(15,827)
Proceeds from exercise of stock options	2,017	1,672	1,649
Tax benefit from stock based awards	0	0	1,846
Increase (decrease) in overdrafts	(9,899)	10,746	6,869
Proceeds from issuance of non-controlling interests	9,982	11,846	217,065
Purchase of non-controlling interests	(120)	(2,099)	(1,095)
Distributions to non-controlling interests	(10,500)	(10,555)	(12,637)
Net cash provided by (used in) financing activities	(21,646)	292,311	1,014,420
Net increase in cash and cash equivalents	23,520	84,594	11,081
Cash and cash equivalents at beginning of period	99,029	14,435	3,354
Cash and cash equivalents at end of period	122,549	99,029	14,435
Supplemental Information
Cash paid for interest	149,156	142,640	103,166
Cash paid for taxes	64,991	70,756	79,420
Liabilities for purchases of property and equipment	30,043	32,861	36,744
Select
Operating activities
Net income	220,645	125,270	135,996
Adjustments to reconcile net income to net cash provided by operating activities:
Distributions from unconsolidated subsidiaries	20,006	20,476	13,969
Depreciation and amortization	160,011	145,311	104,981
Provision for bad debts	79,491	69,093	59,372
Equity in earnings of unconsolidated subsidiaries	(21,054)	(19,943)	(16,811)
Loss on extinguishment of debt	6,527	11,626	0
Gain on sale of assets and businesses	(10,349)	(46,488)	(1,098)
Gain on sale of equity investment	0	(2,779)	(29,647)
Impairment of equity investment	0	5,339	0
Stock compensation expense	19,284	17,413	14,985
Amortization of debt discount, premium and issuance costs	11,130	15,656	9,543
Deferred income taxes	(72,324)	(12,591)	(2,058)
Changes in operating assets and liabilities, net of effects of business combinations:
Accounts receivable	(197,191)	(39,320)	(92,572)
Other current assets	1,597	17,450	(2,503)
Other assets	(886)	9,290	4,713
Accounts payable	3,903	(15,492)	2,345
Accrued expenses	17,341	46,292	7,200
Net cash provided by operating activities	238,131	346,603	208,415
Investing activities
Business combinations, net of cash acquired	(27,390)	(472,206)	(1,061,628)
Purchases of property and equipment	(233,243)	(161,633)	(182,642)
Investment in businesses	(12,682)	(4,723)	(2,347)
Proceeds from sale of assets and businesses	80,350	80,463	1,767
Proceeds from sale of equity investment	0	3,779	33,096
Net cash used in investing activities	(192,965)	(554,320)	(1,211,754)
Financing activities
Borrowings on revolving facilities	970,000	575,000	1,135,000
Payments on revolving facilities	(960,000)	(655,000)	(895,000)
Proceeds from term loans	1,139,487	795,344	623,575
Payments on term loans	(1,179,442)	(438,034)	(29,134)
Revolving facility debt issuance costs	(4,392)	0	0
Borrowings of other debt	46,621	27,721	13,374
Principal payments on other debt	(20,647)	(21,401)	(18,136)
Dividends paid to Holdings	(4,753)	(2,929)	(28,956)
Equity investment by Holdings	2,017	1,672	1,649
Tax benefit from stock based awards	0	0	1,846
Increase (decrease) in overdrafts	(9,899)	10,746	6,869
Proceeds from issuance of non-controlling interests	9,982	11,846	217,065
Purchase of non-controlling interests	(120)	(2,099)	(1,095)
Distributions to non-controlling interests	(10,500)	(10,555)	(12,637)
Net cash provided by (used in) financing activities	(21,646)	292,311	1,014,420
Net increase in cash and cash equivalents	23,520	84,594	11,081
Cash and cash equivalents at beginning of period	99,029	14,435	3,354
Cash and cash equivalents at end of period	122,549	99,029	14,435
Supplemental Information
Cash paid for interest	149,156	142,640	103,166
Cash paid for taxes	64,991	70,756	79,420
Liabilities for purchases of property and equipment	$ 30,043	$ 32,861	$ 36,744