Accumulated Other Comprehensive Income (Reclassifications out of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Income tax expense	$ 2,291	$ 1,419	$ 4,617	$ 2,837
Total, net of tax	(3,892)	(2,523)	(7,806)	(5,042)
Amount Reclassified from AOCI [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Total reclassifications for the period	2	2	4	4
Interest Rate Swaps [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Total reclassifications for the period			(4)	(4)
Interest Rate Swaps [Member] | Amount Reclassified from AOCI [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Total, net of tax	2	2	4	4
Interest Rate Swaps [Member] | Amount Reclassified from AOCI [Member] | Interest Rate Swap [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other expense	3	3	6	6
Income tax expense	$ (1)	$ (1)	$ (2)	$ (2)