Commitments and Contingencies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Lease Commitments
Rental expense under operating leases	$ 3,800	$ 3,800	$ 3,700
Future minimum lease commitments on non-cancelable operating leases
2017	2,581
2018	1,390
2019	704
2020	352
2021	201
Total	5,228
Cash payment schedule associated with lease obligation
2017	5,315
2018	5,470
2019	5,594
2020	5,719
2021	5,848
Thereafter	97,999
Total lease payments	125,945
Less interest portion	(78,359)
Sales leaseback obligation	47,586	$ 47,586
Purchase Commitments
Non-cancelable contracts and purchase orders for inventory	$ 43,900