Stockholders Equity - Annual (Details) $ / shares in Units, $ in Thousands		12 Months Ended
	Dec. 05, 2016	Dec. 31, 2017 USD ($) class $ / shares shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	May 19, 2015 USD ($) $ / shares shares
Equity, Class of Stock [Line Items]
Stockholders' Equity Note, Stock Split, Conversion Ratio	0.25
Adjustments to Additional Paid in Capital, Stock Split		$ 900
Common stock, shares authorized | shares		125,000,000
Preferred stock, shares authorized | shares		10,000,000	10,000,000
Preferred stock, par value (in dollars per share) | $ / shares		$ 0.01	$ 0.01
Number of classes | class		2
Proceeds from Issuance of Preferred Stock, net of issuance costs		$ 0	$ 0	$ 117,194
Preferred stock dividends declared		$ 6,792	$ 6,792	4,075
Treasury Stock, Shares [Roll Forward]
Treasury stock, shares, beginning of period | shares		9,810,802
Purchase of treasury stock, shares | shares		1,401,866
Treasury stock, shares, end of period | shares		12,133,276	9,810,802
Treasury Stock, Cost [Roll Forward]
Treasury stock, cost, beginning of period		$ 153,845
Shares purchased for minimum tax withholding under the Equity Plan or other similar transactions		11,889	$ 8,835	8,907
Purchase of treasury stock, cost		19,500			$ 300
Treasury stock, cost, end of period		$ 186,846	$ 153,845
Treasury Stock, Average Cost Per Share [Roll Forward]
Treasury stock, average cost per share, beginning of period, in dollars per share | $ / shares		$ 15.68
Purchase of treasury stock, average cost per share, in dollars per share | $ / shares		13.90
Treasury stock, average cost per share, end of period, in dollars per share | $ / shares		$ 15.40	$ 15.68
Convertible Preferred Stock, Shares Issued upon Conversion | shares						38.0619
Convertible Preferred Stock, Threshold Percentage of Stock Price Trigger		150.00%
Treasury Stock
Treasury Stock, Shares [Roll Forward]
Shares purchased for minimum tax withholding under the Equity Plan or other similar transactions | shares		822,996
Treasury Stock, Cost [Roll Forward]
Shares purchased for minimum tax withholding under the Equity Plan or other similar transactions		$ 11,889
Treasury Stock, Average Cost Per Share [Roll Forward]
Shares purchased for minimum tax withholding under the Equity Plan or other similar transactions, Average Cost Per Share | $ / shares		$ 14.45
Treasury stock shares received, other | shares		97,612
Treasury stock received, value, other		$ 1,626
Treasury stock received, per share, other | $ / shares		$ 16.66
Convertible Preferred Stock
Equity, Class of Stock [Line Items]
Preferred Stock, Dividend Rate, Percentage		5.625%
Proceeds from Issuance of Preferred Stock, net of issuance costs			$ 117,200
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs		$ 3,600
Preferred Stock, Liquidation Preference Per Share | $ / shares						$ 1,000
Convertible Preferred Stock | Retained Earnings/(Accumulated deficit)
Equity, Class of Stock [Line Items]
Preferred stock dividends declared		$ 6,792	$ 6,800	$ 4,100
Common Stock Class A
Equity, Class of Stock [Line Items]
Common stock, shares authorized | shares		62,500,000	62,500,000
Common stock, par value (in dollars per share) | $ / shares		$ 0.01	$ 0.01
Treasury Stock, Shares [Roll Forward]
Treasury stock, shares, beginning of period | shares		9,810,802
Treasury stock, shares, end of period | shares		12,133,276	9,810,802
Treasury Stock, Cost [Roll Forward]
Treasury stock, cost, beginning of period		$ 153,845
Treasury stock, cost, end of period		$ 186,846	$ 153,845
Common Stock Class B
Equity, Class of Stock [Line Items]
Common stock, shares authorized | shares		62,500,000	62,500,000
Common stock, par value (in dollars per share) | $ / shares		$ 0.01	$ 0.01
Call Option
Equity, Class of Stock [Line Items]
Option indexed to Issuer's Equity, Value						$ 15,900
Maximum
Equity, Class of Stock [Line Items]
Convertible Preferred Stock, Threshold Consecutive Trading Days		30 days
Maximum | Call Option
Equity, Class of Stock [Line Items]
Option Indexed to Issuer's Equity, Strike Price | $ / shares		$ 33.54
Minimum
Equity, Class of Stock [Line Items]
Convertible Preferred Stock, Threshold Consecutive Trading Days		20 days
Minimum | Call Option
Equity, Class of Stock [Line Items]
Option Indexed to Issuer's Equity, Strike Price | $ / shares		$ 26.27