|
CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)
|
Dec. 31, 2014
|
Dec. 31, 2013
|
Dec. 31, 2012
|
| Treasury stock, shares |
36,769 |
32,684 |
|
| Class A common stock |
|
|
|
| Common stock (temporary equity), par value (in dollars per share) |
0.01 |
0.01 |
|
| Common stock (temporary equity), shares issued (in shares) |
173,150 |
173,150 |
|
| Common stock (temporary equity), shares outstanding (in shares) |
136,381 |
140,466 |
|
| Common stock, par value (in dollars per share) |
0.01 |
0.01 |
|
| Common stock, share authorized (in shares) |
524,173,073 |
524,173,073 |
|
| Common stock, shares issued (in shares) |
21,423,839 |
21,412,804 |
|
| Common stock, shares outstanding (in shares) |
21,423,839 |
21,412,804 |
|
| Class B common stock |
|
|
|
| Common stock, share authorized (in shares) |
75,826,927 |
75,826,927 |
|
| Common stock, shares issued (in shares) |
75,826,927 |
75,826,927 |
75,826,927 |
| Common stock, shares outstanding (in shares) |
75,826,927 |
75,826,927 |
|