Shareholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands						1 Months Ended	12 Months Ended
	Oct. 11, 2013	Sep. 25, 2013	Oct. 30, 2008	Jul. 03, 2008	Jun. 15, 2007	Feb. 28, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2010	Dec. 31, 2015
Preferred equity investment
Consideration that the shareholders would have received under merger agreement before termination (in dollars per share)					$ 67.00
Total consideration from the termination of the Merger Agreement				$ 1,475,000
Non-refundable cash termination fee from the termination of the Merger Agreement				225,000
Investment in preferred equity from the termination of the Merger Agreement				$ 1,250,000
Repurchase value of preferred stock								$ 649,518
Changes in each class of the Company's Preferred Stock
Changes in the Company's outstanding Preferred Stock							0		0
Affiliates of Fortress Centerbridge and W F Investment Holdings
Preferred equity investment
Exchange agreement amount paid	$ 649,500
Maximum | Affiliate of Fortress Investment Group LLC
Preferred equity investment
Ownership interest in Spin-Off entity (as a percent)		9.90%
Series B Preferred Stock
Preferred equity investment
Issuance of preferred stock (in shares)			12,500
Repurchase value of preferred stock										$ 11,200
Number of shares held							0	12,275	12,275		0
Changes in each class of the Company's Preferred Stock
Shares outstanding at the beginning of the period								12,275
Repurchase of Preferred Stock (in shares)								(2,525)		(225)
Impact of exchange transaction								(9,750)
Shares outstanding at the end of the period							0		12,275
Series B Preferred Stock | Centerbridge Partners LP
Changes in each class of the Company's Preferred Stock
Repurchase of Preferred Stock (in shares)	(2,300)
Series B Preferred Stock | Wells Fargo Investment Holdings LLC
Changes in each class of the Company's Preferred Stock
Repurchase of Preferred Stock (in shares)						(225)
Series B Preferred Stock | Affiliate of Fortress Investment Group LLC
Changes in each class of the Company's Preferred Stock
Repurchase of Preferred Stock (in shares)	(9,750)
Series B Preferred Stock | Affiliate of Fortress Investment Group LLC
Preferred equity investment
Number of shares of preferred stock provided with the right to exchange as per the Exchange Agreement		9,750
Ceiling price at which the shares of preferred stock are redeemable at maturity (in dollars per share)		$ 67
Series C Preferred Stock
Preferred equity investment
Number of shares held							8,624	8,624			8,624
Number of shares of common stock issued to each share of Series C preferred stock on conversion											1,000
Changes in each class of the Company's Preferred Stock
Shares outstanding at the beginning of the period							8,624
Repurchase of Preferred Stock (in shares)								(5,929)
Impact of exchange transaction								14,553
Shares outstanding at the end of the period							8,624	8,624
Series C Preferred Stock | Affiliate of Fortress Investment Group LLC
Preferred equity investment
Issuance of preferred stock (in shares)	14,553
Repurchase price of preferred stock (in dollars per share)		$ 67
Changes in each class of the Company's Preferred Stock
Repurchase of Preferred Stock (in shares)	(5,929)
Series C Preferred Stock | Affiliate of Fortress Investment Group LLC
Preferred equity investment
Number of shares held						8,624
Changes in each class of the Company's Preferred Stock
Shares outstanding at the end of the period						8,624