Accumulated Other Comprehensive Income Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Gross of tax reclassifications	$ 191	$ 4,593	$ 4,569	$ 4,710
Net of tax reclassifications	114	2,756	2,742	2,826
Beginning balance	9,658	7,636	7,642	6,503
Current-period change, net of tax	510	80	2,526	1,213
Ending balance	10,168	7,716	10,168	7,716
Income tax expense (benefit) associated with current-period change	342	(275)	1,001	(9)
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Beginning balance	0	(8)	(8)	12
Current-period change, net of tax	0	3	8	(17)
Ending balance	0	(5)	0	(5)
Income tax expense (benefit) associated with current-period change	0	2	6	(12)
Accumulated Translation Adjustment [Member]
Beginning balance	2,592	2,382	1,675	2,069
Current-period change, net of tax	58	(48)	975	265
Ending balance	2,650	2,334	2,650	2,334
Income tax expense (benefit) associated with current-period change	41	(361)	(40)	(632)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Beginning balance	7,066	5,262	5,975	4,422
Current-period change, net of tax	452	125	1,543	965
Ending balance	7,518	5,387	7,518	5,387
Income tax expense (benefit) associated with current-period change	$ 301	$ 84	$ 1,035	$ 635