Stockholders' Equity (Dividend Restrictions) (Details) - USD ($) |
1 Months Ended | 12 Months Ended | ||||||
|---|---|---|---|---|---|---|---|---|
Oct. 16, 2015 |
Dec. 04, 2013 |
Aug. 16, 2013 |
Aug. 31, 2012 |
Dec. 31, 2015 |
Dec. 31, 2016 |
Aug. 19, 2016 |
Oct. 02, 2015 |
|
| Class of Stock [Line Items] | ||||||||
| Maximum dividend payment which may be paid without prior approval from Colorado Division of Insurance | $ 125,000,000.0 | |||||||
| Dividends payable | $ 3,000,000 | |||||||
| Common Class A | ||||||||
| Class of Stock [Line Items] | ||||||||
| Common stock, dividends declared (in dollars per share) | $ 0.36 | $ 0.36 | ||||||
| Common stock, dividend paid (in dollar per share) | $ 0.36 | $ 0.36 | ||||||
| Common Class B | ||||||||
| Class of Stock [Line Items] | ||||||||
| Common stock, dividends declared (in dollars per share) | $ 0.18 | $ 0.18 | ||||||
| Common stock, dividend paid (in dollar per share) | $ 0.18 | $ 0.18 | ||||||
| Dividend Declared | ||||||||
| Class of Stock [Line Items] | ||||||||
| Dividends payable | $ 3,500,000 | |||||||
| Subsidiaries | Dividend Declared | ||||||||
| Class of Stock [Line Items] | ||||||||
| Dividends payable | $ 15,500,000 | |||||||