Schedule II - Valuation and Qualifying Accounts - Valuation and Qualifying Accounts (Details) - Allowance for Doubtful Accounts [Member] - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Allowance for doubtful accounts, Balance $ 4,380 $ 3,198 $ 2,465
Additions Charged to costs and expenses 3,298 1,928 881
Additions Charged to other accounts [1] 1,058 1,152 2,717
Allowance for doubtful accounts, Deductions [2] 2,835 1,898 2,865
Allowance for doubtful accounts, Balance $ 5,901 $ 4,380 $ 3,198
[1] Amounts primarily include the allowance for contractual adjustments related to our non-emergency transportation services operating segment that are recorded as adjustments to non-emergency transportation services revenue. Amount additionally includes impact from change in foreign currency rates.
[2] Write-offs, net of recoveries