Shareholders' Equity and Common Stock Equivalents (Details 3)	12 Months Ended
	Dec. 31, 2016 $ / shares shares
Summary of changes in outstanding restricted common stock units
Beginning balance, Total Outstanding, Units | shares	1,442,325
Granted, Total Outstanding Units | shares	370,175	[1]
Vested, Total Outstanding Units | shares	0
Forfeited, Total Outstanding Units | shares	(49,310)
Distributed, Total Outstanding Units | shares	(343,922)	[2]
Ending balance, Total Outstanding, Units | shares	1,419,268
Beginning balance, Total Outstanding, Weighted Average Grant Date Fair Value per Unit | $ / shares	$ 24.29
Granted, Total Outstanding, Weighted Average Grant Date Fair Value per Unit | $ / shares	31.75	[1]
Vested, Total Outstanding, Weighted Average Grant Date Fair Value per Unit | $ / shares	0
Forfeited, Total Outstanding, Weighted Average Grant Date Fair Value per Unit | $ / shares	26.01
Distributed, Total Outstanding, Weighted Average Grant Date Fair Value per Unit | $ / shares	18.28	[2]
Ending balance, Total Outstanding, Weighted Average Grant Date Fair Value per Unit | $ / shares	$ 27.63
Beginning balance, Vested, Units | shares	849,912
Granted, Vested, Units | shares	0	[1]
Vested, Vested, Units | shares	262,074
Forfeited, Vested, Units | shares	0
Distributed, Vested, Units | shares	(343,922)	[2]
Ending balance, Vested, Units | shares	768,064
Beginning balance, Vested, Weighted Average Grant Date Fair Value per Unit | $ / shares	$ 15.51
Granted, Weighted Average Grant Date Fair Value per Unit | $ / shares	0	[1]
Vested, Weighted Average Grant Date Fair Value per Unit | $ / shares	22.92
Forfeited, Weighted Average Grant Date Fair Value per Unit | $ / shares	0
Distributed, Vested, Weighted Average Grant Date Fair Value per Unit | $ / shares	18.28	[2]
Ending balance, Vested, Weighted Average Grant Date Fair Value per Unit | $ / shares	$ 16.80

[1] Includes dividends reinvested into additional restricted common stock units.

[2] Includes distributed units which were utilized to satisfy withholding taxes due on the distribution.