Statements of Condensed Consolidated Total Equity (USD $) In Thousands, unless otherwise specified	Total	Preferred shares at par value	Common shares at par value Class A common shares at par value	Common shares at par value Class B common shares at par value	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income/(loss)	Common shares held by a subsidiary	Non-controlling interests
Balance at Dec. 31, 2012	$ 938,323	$ 0	$ 1,029	$ 181	$ 982,106	$ 39,202	$ (86,381)	$ (181)	$ 2,367
Increase (Decrease) in Stockholders' Equity
Share-based compensation	3,915				3,915
Exercised stock options and vested share awards	3		3
Comprehensive loss:
Net losses attributable to common shares	(29,669)					(29,752)			83
Other comprehensive loss	(23,737)						(23,743)		6
Balance at Jun. 30, 2013	888,835	0	1,032	181	986,021	9,450	(110,124)	(181)	2,456
Balance at Dec. 31, 2013	910,645	0	1,036	181	992,860	7,643	(93,317)	(181)	2,423
Increase (Decrease) in Stockholders' Equity
Share-based compensation	3,087				3,087
Exercised stock options and vested share awards	2		2
Comprehensive loss:
Net losses attributable to common shares	(14,648)					(14,675)			27
Other comprehensive loss	(41,014)						(40,165)		(849)
Balance at Jun. 30, 2014	$ 858,072	$ 0	$ 1,038	$ 181	$ 995,947	$ (7,032)	$ (133,482)	$ (181)	$ 1,601