Derivatives (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Derivative [Line Items]
Fair value of collateral pledged to secure interest rate contracts	$ 2,000		$ 2,000		$ 7,000
Incremental interest expense paid to interest rate swap counterparties	830	$ 831	1,700	$ 1,700
2011 Interest Rate Swap
Derivative [Line Items]
Notional amount of interest rate derivatives	$ 93,500		$ 93,500
Fixed rate payments, interest rate	5.50%		5.50%		5.50%
Variable rate payment rate	1.75%		1.75%		1.75%