Investment in Unconsolidated Entities (Summary of Financial Information of Investment) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Company’s share in net earnings of unconsolidated entities	$ 5,174	$ 2,697	$ 7,739	$ 4,543
Assets	910,248		910,248			$ 875,539
Liabilities	313,818		313,818			325,533
Stockholders' Equity Attributable to Parent	575,759	493,470	575,759	493,470	$ 542,982	523,168	$ 480,869	$ 468,351
Stockholders' Equity Attributable to Noncontrolling Interest	8,186	5,173	8,186	5,173	10,900	13,227	4,788	17,281
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	583,945	498,643	583,945	498,643	553,882	536,395	485,657	485,632
Liabilities and Equity	910,248		910,248			875,539
Total revenues	232,833	183,506	446,100	352,134
Net income	34,837	16,124	51,553	27,615
Cash		34,383		34,383				38,315
Schedule of Equity Method Investments [Line Items]
Stockholders' Equity Attributable to Noncontrolling Interest	8,186	5,173	8,186	5,173	10,900	13,227	4,788	17,281
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	583,945	498,643	583,945	498,643	553,882	536,395	485,657	485,632
Total revenues	232,833	183,506	446,100	352,134
Net income	34,837	16,124	51,553	27,615
Equity in income of unconsolidated entities	5,174	2,697	7,739	4,543
Assets	910,248		910,248			875,539
Cash		34,383		34,383				38,315
Liabilities	313,818		313,818			325,533
Stockholders' Equity Attributable to Parent	575,759	493,470	575,759	493,470	$ 542,982	523,168	$ 480,869	$ 468,351
Liabilities and Equity	910,248		910,248			875,539
Equity Method Investment, Nonconsolidated Investee or Group of Investees
Income Statement [Abstract]
Company’s share in net earnings of unconsolidated entities	5,174	2,697	7,739	4,543
Assets	143,868		143,868			121,674
Liabilities	82,417		82,417			67,733
Stockholders' Equity Attributable to Parent	30,563		30,563			25,910
Stockholders' Equity Attributable to Noncontrolling Interest	30,888		30,888			28,031
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	61,451		61,451			53,941
Liabilities and Equity	143,868		143,868			121,674
Total revenues	52,948	43,261	88,313	74,358
Net income	10,611	5,457	16,161	9,237
Cash	15,917		15,917			11,699
Schedule of Equity Method Investments [Line Items]
Stockholders' Equity Attributable to Noncontrolling Interest	30,888		30,888			28,031
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	61,451		61,451			53,941
Total revenues	52,948	43,261	88,313	74,358
Net income	10,611	5,457	16,161	9,237
Equity in income of unconsolidated entities	5,174	2,697	7,739	4,543
Accounts and Other Receivables, Net, Current	1,432		1,432			3,252
Financing Receivable, after Allowance for Credit Loss	7,342		7,342			5,864
Financing Receivable, Held-for-Sale	29,482		29,482			23,143
Inventory, Net	83,718		83,718			73,704
Other Assets, Current	5,977		5,977			4,012
Accounts Payable, Current	5,814		5,814			1,726
Accrued Liabilities, Current	8,377		8,377			7,784
Notes Payable, Current	68,226		68,226			58,223
Costs and Expenses	42,337	$ 37,804	72,152	$ 65,121
Assets	143,868		143,868			121,674
Cash	15,917		15,917			11,699
Liabilities	82,417		82,417			67,733
Stockholders' Equity Attributable to Parent	30,563		30,563			25,910
Liabilities and Equity	$ 143,868		$ 143,868			$ 121,674