Income Taxes- Deferred tax valuation (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Valuation Allowance, Deferred Tax Asset [Roll Forward] | |||
| Balance, beginning of year | $ 15,231 | $ 12,518 | $ 7,927 |
| Increase in valuation allowance for state credits | 0 | 0 | 2,277 |
| Other changes | 1,973 | 2,713 | 2,314 |
| Balance, end of year | $ 17,204 | $ 15,231 | $ 12,518 |