Income Taxes (Significant Components of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Timing of expense recognition	$ 44,761	$ 20,832
Net operating losses	23,711	8,611
Goodwill	26,658
Other, net	17,098	18,828
Deferred tax assets	112,228	48,271
Valuation Allowance	(2,212)	(1,150)
Net deferred tax assets	110,016	47,121
Deferred tax liabilities:
Intangible assets, due primarily to purchase accounting	(15,309)	(36,862)
Fixed assets, due primarily to purchase accounting	(75,461)	(75,998)
Construction contract accounting	(13,464)	(9,435)
Joint ventures	(24,331)	(9,853)
Other	(16,567)	(20,411)
Deferred tax liabilities	(145,132)	(152,559)
Net deferred tax liabilities	(35,116)	(105,438)
Net Deferred Tax Liabilities
Deferred tax assets	570	83
Deferred tax liabilities	(35,686)	(105,521)
Net deferred tax liabilities	$ (35,116)	$ (105,438)