Unconsolidated Subsidiaries (Schedule) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Variable Interest Entity [Line Items]
Revenues	$ 32,603	$ 31,440	$ 114,052	$ 96,321
Gross profit	6,187	6,095	28,240	16,365
Variable interest entity, not primary beneficiary
Variable Interest Entity [Line Items]
Revenues	187,488	205,838	552,610	570,902
Gross profit	20,059	22,359	53,826	63,827
Income before income taxes	$ 17,827	$ 17,408	$ 49,080	$ 48,986