Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
AOCI Attributable to Parent, Net of Tax
Beginning balance			$ 932,264
Other comprehensive income (loss) before reclassifications	$ (336)	$ 228	811	$ (107)
Reclassification adjustment for (losses) gains included in net income (loss)	0	0	0	4
Ending balance	937,953		937,953
AOCI Attributable to Parent [Member]
AOCI Attributable to Parent, Net of Tax
Beginning balance	(3,058)	(3,948)	(4,205)	(3,617)
Ending balance	$ (3,394)	$ (3,720)	$ (3,394)	$ (3,720)