Schedule of status of awards other than options, and changes during the period (Details) (Class A common shares, USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
2007 performance share plan
Aggregate intrinsic value
Outstanding at end of the period	$ 0
Deferred compensation | 2009 share award and incentive plan
Share-based compensation plans
Options, vested and expected to vest, outstanding, number	0
Shares
Outstanding at the beginning of the period (in shares)	1,343,649	485,020
Share-based compensation other than options granted in period (in shares)	618,170	1,042,900
Vested (in shares)	(344,388)	(130,134)
Forfeited, cancelled or expired (in shares)	(135,604)	(54,137)
Outstanding at the end of the period (in shares)	1,481,827	1,343,649
Weighted average exercise price
Equity instruments other than options, outstanding, weighted average exercise price (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Equity instruments other than options, grants in period, weighted average exercise price (in dollars per share)	$ 0.01	$ 0.01
Equity instruments other than options, vested and issued in period, weighted average exercise price (in dollars per share)	$ 0.01	$ 0.01
Equity instruments other than options, forfeited and expired in period, weighted average exercise price (in dollars per share)	$ 0.01	$ 0.01
Performance shares | 2007 performance share plan
Shares
Outstanding at the beginning of the period (in shares)	0	172,229
Share-based compensation other than options granted in period (in shares)	0	0
Vested (in shares)	0	(108,802)
Forfeited, cancelled or expired (in shares)	0	(63,427)
Outstanding at the end of the period (in shares)	0	0
Weighted average exercise price
Equity instruments other than options, outstanding, weighted average exercise price (in dollars per share)	$ 0.00	$ 0.00	$ 0.01
Equity instruments other than options, grants in period, weighted average exercise price (in dollars per share)	$ 0.00	$ 0.00
Equity instruments other than options, vested and issued in period, weighted average exercise price (in dollars per share)	$ 0.00	$ 0.01
Equity instruments other than options, forfeited and expired in period, weighted average exercise price (in dollars per share)	$ 0.00	$ 0.01