Quarterly Selected Financial Information (Unaudited) (Details) - USD ($)	3 Months Ended								6 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Revenue	$ 319,074,000	$ 287,688,000	$ 283,861,000	$ 267,211,000	$ 293,977,000	$ 270,844,000	$ 281,988,000	$ 274,297,000	$ 551,072,000	$ 556,285,000	$ 838,760,000	$ 827,129,000	$ 1,157,834,000	$ 1,121,106,000	$ 1,138,370,000
Gross profit	62,106,000	69,495,000	68,398,000	62,010,000	59,066,000	63,967,000	64,941,000	65,839,000	130,408,000	130,780,000	199,903,000	194,747,000	262,009,000	253,813,000	275,508,000
(Loss) income from operations	3,588,000	3,762,000	4,063,000	(371,000)	(28,232,000)	(43,312,000)	2,377,000	984,000	3,692,000	3,361,000	7,454,000	(39,951,000)	11,042,000	(68,183,000)	33,546,000
Net loss	$ (6,461,000)	$ (1,062,000)	$ (508,000)	$ (2,044,000)	$ (29,390,000)	$ (45,120,000)	$ (299,000)	$ (1,874,000)	(2,552,000)	(2,173,000)	(3,614,000)	(47,293,000)	(10,075,000)	(76,683,000)	15,869,000
Basic and diluted (in USD per share)	$ (0.12)	$ (0.02)	$ (0.01)	$ (0.04)	$ (0.57)	$ (0.87)	$ (0.01)	$ (0.03)
Selling, general and administrative expenses		$ 59,751,000	$ 57,404,000	$ 55,830,000	$ 62,124,000	$ 56,167,000	$ 59,050,000	$ 61,196,000	$ 113,235,000	$ 120,246,000	172,986,000	$ 176,413,000	222,721,000	238,537,000	227,895,000
Goodwill impairment					18,400,000	27,900,000							0	46,319,000	0
Intangible and other asset impairments						13,800,000							0	18,121,000	$ 0
Long-lived asset impairment charge						$ 3,000,000.0
Capitalized contract cost, impairment loss					$ 1,300,000								$ 0	$ 1,300,000
Cost of Good Sold
Condensed Financial Statements, Captions [Line Items]
Prior period reclassification adjustment	$ 13,800,000
Selling, General and Administrative Expenses
Condensed Financial Statements, Captions [Line Items]
Prior period reclassification adjustment	$ (13,800,000)
Selling, general and administrative expenses											$ 9,400,000