Description of Business and Significant Accounting Policies (Details)	3 Months Ended
	Mar. 31, 2019 USD ($) financial_institution segment	Mar. 31, 2018 USD ($)	Dec. 31, 2018 financial_institution
Schedule of Accounting Policies [Line Items]
Renewal term	1 year
Number of reportable segments | segment	2
Amortization period of inventories and supplies	24 months
Goodwill and intangible asset impairment	$ 0
Revenue	476,111,000	$ 500,562,000
Costs of services provided	427,265,000	469,252,000
Investment and other income, net	$ 5,203,000	1,796,000
Number of financial institutions holding cash and cash equivalents and marketable securities | financial_institution	1		1
Prior period adjustment
Schedule of Accounting Policies [Line Items]
Revenue		(1,200,000)
Costs of services provided		(700,000)
Investment and other income, net		$ 500,000
Minimum
Schedule of Accounting Policies [Line Items]
Days to notify cancellation of service	30 days
Initial period of service term	60 days
Maximum
Schedule of Accounting Policies [Line Items]
Days to notify cancellation of service	90 days
Initial period of service term	120 days