Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Sep. 19, 2012
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net Income (Loss) Available to Common Shareholders									$ 385,721	$ 39,133	$ (756,143)
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	2,749,044				2,625,000				2,749,044	2,625,000		97,541
Warrants and Rights Outstanding												$ 825
Weighted average shares outstanding - basic (in shares)	62,159,683	62,139,833	62,112,936	62,078,404	61,989,094	61,958,183	61,943,851	61,930,783	62,122,862	61,955,659	14,253,869
Dilutive securities outstanding (in shares)									649,217	275,549	0
Weighted average shares outstanding - diluted (in shares)	62,867,030	62,845,864	62,610,054	62,682,987	62,194,011	62,041,203	62,312,224	62,335,212	62,772,079	62,231,208	14,253,869
Earnings per share - basic (in dollars per share)	$ 0.34	$ 0.49	$ 5.17	$ 0.21	$ 0.24	$ 0.18	$ 0.12	$ 0.09	$ 6.21	$ 0.63	$ (53.05)
Earnings per share - diluted (in dollars per share)	$ 0.33	$ 0.49	$ 5.13	$ 0.21	$ 0.24	$ 0.18	$ 0.12	$ 0.09	$ 6.14	$ 0.63	$ (53.05)
Weighted Average antidilutive securities outstanding (in shares)									14,022	21,239	996,208
Stock options
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Weighted Average antidilutive securities outstanding (in shares)									13,792	16,511	20,700
Warrant [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Weighted Average antidilutive securities outstanding (in shares)									0	0	954,754
Restricted shares
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Weighted Average antidilutive securities outstanding (in shares)									230	4,728	20,754