Summary Of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jun. 30, 2015
Summary Of Significant Accounting Policies [Line Items]
Allocated Share-based Compensation Expense	$ 7,891	$ 6,914	$ 6,007
Unamortized Debt Issuance Expense	10,639	10,852
Purchase accounting adjustments		(304)
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	$ 0	$ 0	$ 0
Ecova [Member]
Summary Of Significant Accounting Policies [Line Items]
Owners percentage interest				80.20%
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Lessee Leasing Arrangements, Operating Leases, Term of Contract	1 year
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Lessee Leasing Arrangements, Operating Leases, Term of Contract	45 years