Common Shares (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Common shares
Common stock dividend declared (in dollars per share)		$ 0.06	$ 0.06
Cash dividends paid	$ 17,100	$ 50,924	$ 69,363	$ 59,145
Shares repurchased		300,000	10,600,000
Share price of shares purchased (in dollars per share)	$ 8.64	$ 8.64	$ 12.98	$ 18.19
Total aggregate amount of shares purchased		$ 1,700	$ 99,600
Capital Units, Authorized	825,000,000	825,000,000
Common Stock, Shares Authorized	800,000,000	800,000,000	800,000,000
Common Stock, Par or Stated Value Per Share	$ 0.001	$ 0.001	$ 0.001
Preferred Stock, Shares Authorized	25,000,000	25,000,000
Preferred shares, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred shares, shares issued	0	0
Preferred Stock, Shares Outstanding	0	0
Treasury shares reissued during the year		0	0	0
Officers and Directors
Common shares
Restricted stock awarded to executive officers, key employees & directors		3,919,696	3,530,033	1,926,861
Restricted shares awarded, average market price (in dollars per share)	$ 9.85	$ 9.85	$ 10.09	$ 19.53