Financial Information for the Company and Its Subsidiaries - Summary of Condensed Consolidating Statement of Operations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Financial Statements, Captions [Line Items]
Revenue before provision for doubtful accounts	$ 189,999	$ 184,702	$ 177,494	$ 161,213	$ 114,252	$ 103,116	$ 100,530	$ 89,563	$ 735,109	$ 413,850	$ 219,704
Provision for doubtful accounts									(21,701)	(6,389)	(3,206)
Revenue									713,408	407,461	216,498
Salaries, wages and benefits									407,962	239,639	152,609
Professional fees									37,171	19,019	8,896
Supplies									37,569	19,496	11,349
Rents and leases									10,049	7,838	5,576
Other operating expenses									80,572	42,777	20,171
Depreciation and amortization									17,090	7,982	4,278
Interest expense, net									37,250	29,769	9,191
Debt extinguishment costs				(9,500)					9,350
Sponsor management fees											1,347
Transaction-related expenses									7,150	8,112	41,547
Total expenses									644,163	374,632	254,964
(Loss) income from continuing operations before income taxes	19,935	22,287	20,291	6,732	7,506	10,311	10,020	4,992	69,245	32,829	(38,466)
(Benefit from) provision for income taxes									25,975	12,325	(5,272)
Income (loss) from continuing operations									43,270	20,504	(33,194)
Loss from discontinued operations, net of income taxes									(691)	(101)	(1,698)
Net income (loss)	12,280	14,364	12,197	3,738	4,365	6,450	5,909	3,679	42,579	20,403	(34,892)
Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Salaries, wages and benefits									5,249	2,267	17,320
Interest expense, net									35,327	29,512	9,191
Debt extinguishment costs									9,350
Total expenses									49,926	31,779	26,511
(Loss) income from continuing operations before income taxes									(49,926)	(31,779)	(26,511)
Equity in earnings of subsidiaries									73,538	40,251	(12,014)
(Benefit from) provision for income taxes									(18,967)	(11,931)	(3,633)
Income (loss) from continuing operations									42,579	20,403	(34,892)
Net income (loss)									42,579	20,403	(34,892)
Combined Subsidiary Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Revenue before provision for doubtful accounts									700,407	412,161	219,704
Provision for doubtful accounts									(20,700)	(6,389)	(3,206)
Revenue									679,707	405,772	216,498
Salaries, wages and benefits									388,749	236,182	135,289
Professional fees									34,149	18,806	8,896
Supplies									35,686	19,382	11,349
Rents and leases									9,282	7,816	5,576
Other operating expenses									72,626	42,121	20,171
Depreciation and amortization									15,882	7,874	4,278
Interest expense, net									22
Sponsor management fees											1,347
Transaction-related expenses									6,716	8,112	41,547
Total expenses									563,112	340,293	228,453
(Loss) income from continuing operations before income taxes									116,595	65,479	(11,955)
(Benefit from) provision for income taxes									44,294	24,583	(1,639)
Income (loss) from continuing operations									72,301	40,896	(10,316)
Loss from discontinued operations, net of income taxes									(691)	(101)	(1,698)
Net income (loss)									71,610	40,795	(12,014)
Combined Non-Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Revenue before provision for doubtful accounts									34,702	1,689
Provision for doubtful accounts									(1,001)
Revenue									33,701	1,689
Salaries, wages and benefits									13,964	1,190
Professional fees									3,022	213
Supplies									1,883	114
Rents and leases									767	22
Other operating expenses									7,946	656
Depreciation and amortization									1,208	108
Interest expense, net									1,901	257
Transaction-related expenses									434
Total expenses									31,125	2,560
(Loss) income from continuing operations before income taxes									2,576	(871)
(Benefit from) provision for income taxes									648	(327)
Income (loss) from continuing operations									1,928	(544)
Net income (loss)									1,928	(544)
Consolidating Adjustments [Member]
Condensed Financial Statements, Captions [Line Items]
Equity in earnings of subsidiaries									(73,538)	(40,251)	12,014
Income (loss) from continuing operations									(73,538)	(40,251)	12,014
Net income (loss)									$ (73,538)	$ (40,251)	$ 12,014