Debt (Revolving Credit Facility Under The Senior Credit Agreement) (Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Apr. 30, 2017	Mar. 31, 2017	Mar. 31, 2016
Line of Credit Facility [Line Items]
Repayments of revolving credit facility		$ 110,000	$ 50,000
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity		$ 1,000,000
Line of credit facility, commitment fee		0.25%
Revolving credit facility, maturity date		Feb. 05, 2020
Repayments of revolving credit facility		$ 110,000
Revolving Credit Facility [Member] | Subsequent Event [Member]
Line of Credit Facility [Line Items]
Repayments of revolving credit facility	$ 190,000
Minimum [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Basis spread on variable interest rate		1.375%
Minimum [Member] | Revolving Credit Facility [Member] | Base Rate [Member]
Line of Credit Facility [Line Items]
Basis spread on variable interest rate		0.375%
Maximum [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Basis spread on variable interest rate		2.00%
Maximum [Member] | Revolving Credit Facility [Member] | Base Rate [Member]
Line of Credit Facility [Line Items]
Basis spread on variable interest rate		1.00%