Investments in Affiliates - Additional Information (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2019 USD ($) Investment	Dec. 31, 2018 USD ($)	Jun. 30, 2018 USD ($)
Investments In And Advances To Affiliates [Line Items]
Number of Investments in Foreign Entities | Investment	13
Number of Investments in Real Estate Entities | Investment	4
Joint Venture Unconsolidated [Member]
Investments In And Advances To Affiliates [Line Items]
Total assets	$ 321,125	$ 312,102	$ 310,337
Joint Venture Unconsolidated [Member] | Texas [Member]
Investments In And Advances To Affiliates [Line Items]
Equity Method Investments	14,200	16,300	24,000
Other Affiliates [Member] | Joint Venture Unconsolidated [Member]
Investments In And Advances To Affiliates [Line Items]
Total assets	321,100
Equity Method Investments	82,109	$ 84,354	$ 99,495
Variable Interest Entity, Not Primary Beneficiary [Member] | Joint Venture Unconsolidated [Member] | Asphalt Terminal Entity [Member]
Investments In And Advances To Affiliates [Line Items]
Total assets	$ 28,100
Minimum [Member] | Foreign Affiliates [Member] | Joint Venture Unconsolidated [Member] | Equity Method Investment Directly Owned [Member]
Investments In And Advances To Affiliates [Line Items]
Ownership percentage	25.00%
Minimum [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Real Estate Entities [Member] | Joint Venture Unconsolidated [Member]
Investments In And Advances To Affiliates [Line Items]
Total assets	$ 400
Minimum [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Foreign Affiliates [Member] | Joint Venture Unconsolidated [Member]
Investments In And Advances To Affiliates [Line Items]
Total assets	$ 200
Maximum [Member] | Foreign Affiliates [Member] | Joint Venture Unconsolidated [Member] | Equity Method Investment Indirectly Owned [Member]
Investments In And Advances To Affiliates [Line Items]
Ownership percentage	50.00%
Maximum [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Real Estate Entities [Member] | Joint Venture Unconsolidated [Member]
Investments In And Advances To Affiliates [Line Items]
Total assets	$ 52,300
Maximum [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Foreign Affiliates [Member] | Joint Venture Unconsolidated [Member]
Investments In And Advances To Affiliates [Line Items]
Total assets	$ 76,600