Earnings Per Common Share Series A-1 Preferred Stock (Details) (USD $)	12 Months Ended			0 Months Ended	3 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Feb. 13, 2013	Mar. 31, 2013	Jul. 23, 2012	Oct. 02, 2012
Class of Stock [Line Items]
Net proceeds from Series A-1 Preferred Stock issuance	$ 0	$ 0	$ 349,418,000
Unpaid dividends paid upon conversion of preferred stock	0	2,139,000	4,375,000
Class A Common Stock [Member]
Class of Stock [Line Items]
Conversion of shares to Class A Common Stock, shares				5,984,232
Shares issued upon conversion of Series A-1 Preferred Stock, per share						17.1
Optional Preferred Stock Conversion Rate						130.00%
Optional Preferred Stock Conversion Price						$ 76.03
Series A-1 Preferred Stock [Member]
Class of Stock [Line Items]
Series A-1 Preferred Stock shares issued							350,000
Issuance price							$ 1,000.00
Net proceeds from Series A-1 Preferred Stock issuance			349,400,000
Convertible preferred stock coupon rate						5.00%
Preferred Stock conversion price						58.49
Premium on conversion price						4.50%
Unpaid dividends paid upon conversion of preferred stock					$ 2,100,000