Stockholders Equity - Annual (Details) $ / shares in Units, $ in Thousands		12 Months Ended
	Dec. 05, 2016 USD ($)	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) $ / shares shares	Dec. 31, 2016 USD ($)	May 19, 2015 USD ($) $ / shares shares
Equity, Class of Stock [Line Items]
Adjustments to Additional Paid in Capital, Stock Split	$ 900
Stockholders' Equity Note, Stock Split, Conversion Ratio	0.25
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
Preferred stock dividends declared		$ 6,792	$ 6,792	$ 6,792
Treasury Stock, Shares [Roll Forward]
Treasury stock, shares, beginning of period | shares		12,133,276
Purchase of treasury stock, shares | shares		2,164,186
Treasury stock, shares, end of period | shares		15,336,871	12,133,276
Treasury Stock, Cost [Roll Forward]
Treasury stock, cost, beginning of period		$ 186,846
Shares purchased for minimum tax withholding under the Equity Plan or other similar transactions		12,310	$ 11,889	8,835
Purchase of treasury stock, cost		31,762
Treasury stock, cost, end of period		$ 234,142	$ 186,846
Treasury Stock, Average Cost Per Share [Roll Forward]
Treasury stock, average cost per share, beginning of period, in dollars per share | $ / shares		$ 15.40
Purchase of treasury stock, average cost per share, in dollars per share | $ / shares		14.68
Treasury stock, average cost per share, end of period, in dollars per share | $ / shares		$ 15.27	$ 15.40
Convertible Preferred Stock, Shares Issued upon Conversion | shares					38.0619
Convertible Preferred Stock, Threshold Percentage of Stock Price Trigger		150.00%
Embedded Cash Conversion Option		$ 21,195	$ 0	0
Treasury Stock
Treasury Stock, Shares [Roll Forward]
Shares purchased for minimum tax withholding under the Equity Plan or other similar transactions | shares		803,236
Treasury Stock, Cost [Roll Forward]
Shares purchased for minimum tax withholding under the Equity Plan or other similar transactions		$ 12,136
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		$ 15.11
Treasury stock shares received, other | shares		236,173
Treasury stock received, value, other		$ 3,398
Treasury stock received, per share, other | $ / shares		$ 14.39
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	$ 6,792	$ 6,792
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		12,133,276
Treasury stock, shares, end of period | shares		15,336,871	12,133,276
Treasury Stock, Cost [Roll Forward]
Treasury stock, cost, beginning of period		$ 186,846
Treasury stock, cost, end of period		$ 234,142	$ 186,846
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
Convertible Debt | 2022 convertible note
Equity, Class of Stock [Line Items]
Debt Conversion, Converted Instrument, Amount		$ 23,400
Treasury Stock, Cost [Roll Forward]
Purchase of treasury stock, cost		19,500
Treasury Stock, Average Cost Per Share [Roll Forward]
Embedded Cash Conversion Option		$ 29,000