Borrowing Arrangements (Details 2) - Cash flow hedge - Interest rate swap - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Oct. 31, 2012
Interest rate swaps
Aggregate starting notional amount			$ 150,000
Fixed rate (as a percent)	0.7525%
Variable rate basis	LIBOR
Ineffective portion of cash flow hedges recognized	$ 0	$ 0