Share-Based Compensation and Employee Ownership Plans Restricted Shares and Restricted Stock Units (Details) $ / shares in Units, $ in Millions		1 Months Ended	2 Months Ended	3 Months Ended
	Dec. 05, 2016	Mar. 31, 2016 shares	Jan. 31, 2014 shares	Mar. 31, 2018 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stockholders' Equity Note, Stock Split, Conversion Ratio	0.25
Equity Plans | Restricted Shares and Restricted Stock Units (RSUs)
Nonvested Restricted Shares and Restricted Stock Units
Balance outstanding, beginning of period, shares				5,579,293
Granted, shares				2,108,184
Vested, shares				(858,433)
Canceled, shares				0
Forfeited, shares				(21,412)
Balance outstanding, end of period, shares				6,807,632
Weighted-Average Grant Date Fair Value
Balance outstanding, beginning of period, in dollars per share | $ / shares				$ 16.33
Granted, in dollars per share | $ / shares				14.23
Vested, in dollars per share | $ / shares				16.20
Canceled, in dollars per share | $ / shares				0.00
Forfeited, in dollars per share | $ / shares				13.11
Balance outstanding, end of period, in dollars per share | $ / shares				$ 15.71
Unrecognized compensation expense | $				$ 78.8
Weighted-average recognition period for unrecognized compensation expense				2 years 6 months 26 days
Equity Plans | Performance based restricted stock
Nonvested Restricted Shares and Restricted Stock Units
Granted, shares		700,000	481,438
Forfeited, shares				(117,188)
Non-employee Director | Equity Plans | Restricted Stock Units (RSUs)
Nonvested Restricted Shares and Restricted Stock Units
Balance outstanding, end of period, shares				191,962
Weighted-Average Grant Date Fair Value
Granted, shares				0
Maximum
Nonvested Restricted Shares and Restricted Stock Units
Percent of RSU's earned				150.00%
Minimum
Nonvested Restricted Shares and Restricted Stock Units
Percent of RSU's earned				0.00%