Employee Benefit Plans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Minimum number of hours worked by employees to cover under the plan	20 hours
Employees minimum employment period to participate in plan	30 days
Percent of employee's contribution matched half by employer	50.00%
Defined contribution plan, employee's gross salary, percent	5.00%
Defined Contribution Plan, Maximum Annual Contribution Per Employer, Amount	$ 2,500
Employer contributions vesting period	3 years
Employer contributions vesting percentage for year one	33.00%
Employer contributions vesting percentage for year two	66.00%
Employer contributions vesting percentage for year three	100.00%
Defined contribution plan, vested working hours	1000 hours
Defined contribution plan, matching contribution	$ 1,100,000	$ 1,100,000	$ 1,100,000
Severance benefits, annual severance pay awarded, period	14 days
Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Severance benefits, severance pay period	14 days
Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Severance benefits, severance pay period	182 days
Severance costs
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Accrued severance liability	$ 1,455,000	$ 1,356,000	$ 1,581,000