Related Party Transactions (Other Related Party Transactions) (Narrative) (Details)	12 Months Ended
	Dec. 31, 2016 USD ($) employee	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Management [Member] | Subcontracting Arrangement, Construction Services [Member]
Related Party Transaction [Line Items]
Number of additional management employees, subcontracting arrangement | employee	2
Payments, related party	$ 12,900,000
Payables, related party	$ 100,000
Management [Member] | Subcontracting Arrangement, Construction Services [Member] | Subsidiaries [Member]
Related Party Transaction [Line Items]
Number of subsidiaries, non-controlling interests, subcontracting arrangement	1
Management [Member] | Equipment [Member]
Related Party Transaction [Line Items]
Proceeds from sale of equipment, related party	$ 300,000
Management [Member] | Services [Member]
Related Party Transaction [Line Items]
Payments, related party	27,700,000	$ 10,500,000	$ 6,000,000
Payables, related party	3,700,000	2,100,000
Management [Member] | Lease Agreements [Member]
Related Party Transaction [Line Items]
Payments, related party	43,300,000	22,100,000	12,200,000
Payables, related party	300,000	100,000
Executive Officers [Member] | Services [Member] | Related Customer [Member]
Related Party Transaction [Line Items]
Revenue, related party	900,000	900,000	1,000,000
Accounts receivable, related party	400,000	300,000
Executive Officers [Member] | Employee Leasing Arrangements [Member] | Related Customer [Member]
Related Party Transaction [Line Items]
Charges, related party	800,000	800,000	700,000
Receivables, related party	200,000	100,000
Immediate Family Member of Management [Member] | Property Lease [Member]
Related Party Transaction [Line Items]
Payments, related party	48,000	$ 48,000	$ 48,000
Chairman, Board of Directors [Member] | Lease Agreements [Member] | Aircraft [Member]
Related Party Transaction [Line Items]
Payments, related party	$ 2,600,000