Stock Incentive Plans - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	May 22, 2014	May 21, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of options outstanding and exercisable	$ 0
Weighted average remaining contractual term	1 month
Restricted Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted during the year (in shares)	685,872
Aggregate fair value on vest date of restricted common stock awards	$ 5,600,000	$ 11,700,000	$ 6,600,000
Weighted average grant date fair value of restricted common stock (in dollars per share)	$ 15.06	$ 13.05	$ 12.58
Stock based compensation expense, net of taxes	$ 2,400,000	$ 6,800,000	$ 5,600,000
Stock based compensation expense, taxes	1,700,000	$ 4,600,000	$ 3,100,000
Pre-tax compensation cost related to all unvested awards not yet recognized	$ 8,900,000
Weighted average period of recognition	1 year 8 months 12 days
Excluded pre-tax compensation cost	$ 6,400,000
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance-based restricted stock units granted (in shares)	516,700
Restricted Stock Units | Officers
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock for each restricted stock unit granted (in shares)	1
Granted during the year (in shares)	0	409,800	395,900
Restricted Stock Units | Officers | Change in control
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued on change in control date, as a percent of units granted	100.00%
2014 Employee Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized					3,250,000
Number of shares available for grant	2,811,091
Number of shares of common stock reserved for options, restricted stock, restricted stock units and/or stock appreciation right grants					3,757,925
2005 Employee Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant				0	507,925
2007 Director Stock Plan | Restricted Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized	240,080
Number of shares available for grant	27,721
Granted during the year (in shares)	21,912
Award vesting period	3 years
Other Than 2014 Employee Stock Plan, 2005 Employee Stock Plan and 2007 Director Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum term of options outstanding	10 years
Minimum | Restricted Stock Units | Officers
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued, as a percent of units granted	0.00%
Maximum | Restricted Stock Units | Officers
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued, as a percent of units granted	125.00%