Unaudited Quarterly Financial Data - Statement of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Selected Quarterly Financial Results (Unaudited)
Revenue	$ 314,109	$ 305,280	$ 307,722	$ 365,451	$ 393,586	$ 373,545	$ 390,849	$ 404,357	$ 1,292,562	$ 1,562,337	$ 1,586,222
Cost of revenue (exclusive of depreciation and amortization)	254,995	234,222	241,788	292,539	314,858	295,445	303,831	310,601	1,023,544	1,224,735	1,213,403
Selling, general and administrative expenses (exclusive of depreciation and amortization)	45,879	42,837	47,014	50,374	49,678	48,347	51,162	49,677	186,104	198,864	184,908
Depreciation and amortization	25,826	22,095	22,847	23,185	24,421	25,079	24,779	26,624	93,953	100,903	138,077
Impairment of goodwill and other intangible assets					252,399	97,158				349,557	48,127
Related party expense	1,324	1,360	1,146	1,551	1,742	1,430	5,331	998	5,381	9,501	12,403
Operating loss	(13,915)	4,766	(5,073)	(2,198)	(249,512)	(93,914)	5,746	16,457	(16,420)	(321,223)	(10,696)
Other expense (income), net:
Interest expense, net	44,238	43,612	44,440	41,588	43,216	40,573	39,959	39,701	173,878	163,449	155,991
Debt modification and extinguishment costs	9,589						1,404		9,589	1,404	1,067
Sundry expense (income), net	98	(434)	(899)	1,082	(600)	165	(1,311)	2,715	(153)	969	(3,271)
Other expense (income), net	10,867	(10,414)	(584)	(34,657)	10,003	406	2,527	1,493	(34,788)	14,429	(3,030)
Net loss before income taxes	(78,707)	(27,998)	(48,030)	(10,211)	(302,131)	(135,058)	(36,833)	(27,452)	(164,946)	(501,474)	(161,453)
Income tax (expense) benefit	(10,144)	(320)	(661)	(2,459)	(1,953)	3,769	(4,738)	(4,720)	(13,584)	(7,642)	(8,353)
Net loss	(88,851)	(28,318)	(48,691)	(12,670)	(304,084)	(131,289)	(41,571)	(32,172)	(178,530)	(509,116)	(169,806)
Cumulative dividends for Series A Preferred Stock	(915)	(976)	(858)		(597)	(884)	(914)	(914)	(1,309)	(3,309)	(3,655)
Cumulative dividends for Series A Preferred Stock				1,440
Net loss attributable to common stockholders	$ (89,766)	$ (29,294)	$ (49,549)	$ (11,230)	$ (304,681)	$ (132,173)	$ (42,485)	$ (33,086)	$ (179,839)	$ (512,425)	$ (173,461)
Weighted average outstanding common shares	49,172,037	49,170,477	49,169,556	49,065,055	48,720,451	48,545,583	48,488,731	48,524,074
Earnings per share:
Basic and diluted	$ (1.82)	$ (0.60)	$ (1.01)	$ (0.23)	$ (6.27)	$ (2.72)	$ (0.88)	$ (0.68)	$ (3.66)	$ (10.55)	$ (3.52)
ITPS
Selected Quarterly Financial Results (Unaudited)
Revenue	$ 243,537	$ 234,365	$ 243,029	$ 284,112	$ 306,665	$ 292,607	$ 309,840	$ 325,172	$ 1,005,043	$ 1,234,284	$ 1,273,647
Cost of revenue (exclusive of depreciation and amortization)	200,387	183,671	195,835	235,120	250,927	241,867	249,589	259,272	815,013	1,001,655	1,010,320
HS
Selected Quarterly Financial Results (Unaudited)
Revenue	51,623	54,209	49,166	64,049	69,806	62,132	63,440	61,343	219,047	256,721	228,015
Cost of revenue (exclusive of depreciation and amortization)	39,394	39,444	36,148	44,931	53,634	42,717	43,353	40,341	159,917	180,045	151,877
LLPS
Selected Quarterly Financial Results (Unaudited)
Revenue	18,949	16,706	15,527	17,290	17,115	18,806	17,569	17,842	68,472	71,332	84,560
Cost of revenue (exclusive of depreciation and amortization)	$ 15,214	$ 11,107	$ 9,805	$ 12,488	$ 10,297	$ 10,861	$ 10,889	$ 10,988	$ 48,614	$ 43,035	$ 51,206