Revenue Recognition Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 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	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Total revenues	$ 309,687	$ 302,534	$ 297,584	$ 279,541	$ 273,803	$ 261,531	$ 259,875	$ 253,573	$ 1,189,346	$ 1,048,782	$ 1,002,286
Service
Disaggregation of Revenue [Line Items]
Total revenues									1,059,976	921,096	871,458
Product
Disaggregation of Revenue [Line Items]
Total revenues									46,496	50,627	55,496
USF
Disaggregation of Revenue [Line Items]
Total revenues									82,874	77,059	75,332
Business Service
Disaggregation of Revenue [Line Items]
Total revenues									803,880	608,144	498,922
Business Service | Service
Disaggregation of Revenue [Line Items]
Total revenues									719,514	526,707	417,118
Business Service | Product
Disaggregation of Revenue [Line Items]
Total revenues									46,232	50,068	54,971
Business Service | USF
Disaggregation of Revenue [Line Items]
Total revenues									38,134	31,369	26,833
Consumer Service
Disaggregation of Revenue [Line Items]
Total revenues									385,466	440,638	503,364
Consumer Service | Service
Disaggregation of Revenue [Line Items]
Total revenues									340,462	394,389	454,340
Consumer Service | Product
Disaggregation of Revenue [Line Items]
Total revenues									264	559	525
Consumer Service | USF
Disaggregation of Revenue [Line Items]
Total revenues									44,740	45,690	48,499
UNITED STATES
Disaggregation of Revenue [Line Items]
Total revenues									855,255	825,721	851,413
UNITED STATES | Business Service
Disaggregation of Revenue [Line Items]
Total revenues									500,545	421,239
UNITED STATES | Consumer Service
Disaggregation of Revenue [Line Items]
Total revenues									354,710	404,482
CANADA
Disaggregation of Revenue [Line Items]
Total revenues									26,696	27,267	30,252
CANADA | Business Service
Disaggregation of Revenue [Line Items]
Total revenues									6,942	3,549
CANADA | Consumer Service
Disaggregation of Revenue [Line Items]
Total revenues									19,754	23,718
UNITED KINGDOM
Disaggregation of Revenue [Line Items]
Total revenues									66,723	49,430	$ 28,309
UNITED KINGDOM | Business Service
Disaggregation of Revenue [Line Items]
Total revenues									55,721	36,992
UNITED KINGDOM | Consumer Service
Disaggregation of Revenue [Line Items]
Total revenues									11,002	12,438
Other Countries
Disaggregation of Revenue [Line Items]
Total revenues									240,672	146,364
Other Countries | Business Service
Disaggregation of Revenue [Line Items]
Total revenues									240,672	146,364
Other Countries | Consumer Service
Disaggregation of Revenue [Line Items]
Total revenues									$ 0	$ 0