Receivables and Allowance for Doubtful Accounts Receivables and Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Receivables [Line Items]
Accounts Receivable, before Allowance for Credit Loss	$ 70,015		$ 74,528
Receivables, net of allowance for doubtful accounts of $4,349 and $4,883 in 2019 and 2018, respectively	65,666		69,645
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for doubtful accounts	4,349		4,883
Bad debt expense	5,978	$ 5,846
Accounts written off	(6,773)
Recoveries	261
Installment sales receivable [Member]
Receivables [Line Items]
Accounts Receivable, before Allowance for Credit Loss	52,332		54,746
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for doubtful accounts	2,900		3,600
Trade and notes receivables [Member]
Receivables [Line Items]
Accounts Receivable, before Allowance for Credit Loss	17,683		19,782
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for doubtful accounts	$ 1,400		$ 1,300