Accumulated Other Comprehensive Income (Loss) Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2017	Dec. 31, 2016		Mar. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	$ (306)	$ (120)	$ (306)	$ (120)	$ (2,574)	$ (3,262)	[1]	$ (1,261)	$ (456)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	2,325	1,382	2,976	824
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(57)	(241)	(20)	(488)
Other Comprehensive Income (Loss), Net of Tax	2,268	1,141	2,956	336
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	219		219		0	0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	219		219
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0		0
Other Comprehensive Income (Loss), Net of Tax	219		219
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	(2,238)	(5,135)	(2,238)	(5,135)	(2,408)	(2,905)		(4,657)	(3,195)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	170	(478)	667	(1,940)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0	0	0
Other Comprehensive Income (Loss), Net of Tax	170	(478)	667	(1,940)
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	1,713	5,015	1,713	5,015	$ (166)	$ (357)		$ 3,396	$ 2,739
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	1,936	1,860	2,090	2,764
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(57)	(241)	(20)	(488)
Other Comprehensive Income (Loss), Net of Tax	$ 1,879	$ 1,619	$ 2,070	$ 2,276

[1] Derived from audited consolidated financial statements