Derivative Instruments Derivative gain loss table (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Interest Rate Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss)	$ 245	$ 0	$ 488	$ 0
Interest Rate Swap No. 1 [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss)	147	0	293	0
Interest Rate Swap No. 2 [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss)	$ 98	$ 0	$ 195	$ 0