Investments Summary of Assets, Liabilities and Results of Operations for Significant Unconsolidated Joint Ventures (Details) - Significant Unconsolidated Joint Ventures - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Schedule of Investments [Line Items]
Current assets	$ 473,426	$ 476,460
Noncurrent assets	1,404,765	1,159,866
Total assets	1,878,191	1,636,326
Current liabilities	201,792	191,971
Noncurrent liabilities	583,839	422,769
Total liabilities	785,631	614,740
Net sales	910,891	829,590	$ 687,561
Gross profit	496,150	456,518	353,577
Income before income taxes	384,690	332,632	267,805
Net income	$ 229,733	$ 225,791	$ 184,777