Segments and Related Information (Reconciliation of Consolidated Income before Income Taxes to EBITDA) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
EBITDA Reconciliation:
Income before income taxes	$ 138,766	$ 42,039	$ 206,751	$ 37,071
Interest expense, net	14,791	12,639	27,388	24,797
Depreciation and amortization	45,379	40,657	88,282	79,664
Consolidated EBITDA	$ 198,900	$ 95,300	$ 322,400	$ 141,500