Accounting Standards and Significant Accounting Policies - Schedule of summary the changes in the allowances for doubtful accounts (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2019 USD ($)
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period December 31, 2018	$ 4,647
Provisions for losses - accounts receivable	1,664
Collection of accounts previously written off	0
Deductions for accounts charged off or credits issued	(2,465)
Balance, end of period	$ 3,846