Accrued Expenses and Other Liabilities Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accounts Payable and Accrued Liabilities, Current [Abstract]
Accrued stock based compensation	$ 8,712	$ 7,859
Accrued compensation	9,044	5,465
Accrued severance	483	1,428
Accrued and withheld taxes, other than income taxes	1,136	1,149
Financing lease obligation	1,123	996
Accrued health benefits	657	676
Accrued profit sharing	894	627
Other	10,991	9,089
Accrued Liabilities, Current	$ 33,040	$ 27,289