Stockholder's Equity - Quarterly (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		9 Months Ended
	May 19, 2015	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Equity, Class of Stock [Line Items]
Adjustments to Additional Paid in Capital, Stock Split				$ (900)
Preferred stock dividends declared				$ 5,094	$ 5,094
Convertible Preferred Stock, Shares Issued upon Conversion	38.0619
Convertible Preferred Stock, Threshold Percentage of Stock Price Trigger				150.00%
Treasury Stock, Shares [Roll Forward]
Treasury stock, shares, beginning of period				9,810,802
Purchase of treasury stock, shares				0
Treasury stock, shares, end of period		10,602,529		10,602,529
Treasury stock, cost, beginning of period				$ 153,845
Shares purchased for minimum tax withholding under the Equity Plan or other similar transactions				11,433	8,793
Purchase of treasury stock, cost				0
Treasury stock, cost, end of period		$ 165,278		$ 165,278
Treasury stock, average cost per share, beginning of period, in dollars per share				$ 15.68
Purchase of treasury stock, average cost per share, in dollars per share				0.00
Treasury stock, average cost per share, end of period, in dollars per share		$ 15.59		$ 15.59
Treasury Stock
Treasury Stock, Shares [Roll Forward]
Shares purchased for minimum tax withholding under the Equity Plan or other similar transactions				791,727
Shares purchased for minimum tax withholding under the Equity Plan or other similar transactions				$ 11,433
Shares purchased for minimum tax withholding under the Equity Plan or other similar transactions, Average Cost Per Share				$ 14.44
Call Option
Equity, Class of Stock [Line Items]
Option indexed to Issuer's Equity, Value	$ 15,900
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				$ 26.27
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				$ 33.54
Convertible Preferred Stock
Equity, Class of Stock [Line Items]
Preferred stock issuance, net of issuance costs	120,750
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, Dividend Rate, Percentage				5.625%
Preferred Stock, Liquidation Preference Per Share	$ 1,000
Convertible Preferred Stock | Retained Earnings/(Accumulated deficit)
Equity, Class of Stock [Line Items]
Preferred stock dividends declared		$ (1,700)	$ (1,700)	$ 5,094	$ 5,094