Shareholders' Equity and Common Stock Equivalents (Details 3)	12 Months Ended
	Dec. 31, 2015 $ / shares shares
Summary of changes in outstanding restricted common stock units
Beginning balance, Total Outstanding, Units | shares	1,590,138
Granted, Total Outstanding Units | shares	225,180	[1]
Vested, Total Outstanding Units | shares	0
Forfeited, Total Outstanding Units | shares	(66,794)
Distributed, Total Outstanding Units | shares	(306,199)	[2]
Ending balance, Total Outstanding, Units | shares	1,442,325
Beginning balance, Total Outstanding, Weighted Average Grant Date Fair Value per Unit | $ / shares	$ 21.34
Granted, Total Outstanding, Weighted Average Grant Date Fair Value per Unit | $ / shares	34.42	[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	25.60
Distributed, Total Outstanding, Weighted Average Grant Date Fair Value per Unit | $ / shares	16.13	[2]
Ending balance, Total Outstanding, Weighted Average Grant Date Fair Value per Unit | $ / shares	$ 24.29
Beginning balance, Vested, Units | shares	853,054
Granted, Vested, Units | shares	0	[1]
Vested, Vested, Units | shares	303,057
Forfeited, Vested, Units | shares	0
Distributed, Vested, Units | shares	(306,199)	[2]
Ending balance, Vested, Units | shares	849,912
Beginning balance, Vested, Weighted Average Grant Date Fair Value per Unit | $ / shares	$ 14.36
Granted, Weighted Average Grant Date Fair Value per Unit | $ / shares	0	[1]
Vested, Weighted Average Grant Date Fair Value per Unit | $ / shares	19.39
Forfeited, Weighted Average Grant Date Fair Value per Unit | $ / shares	0
Distributed, Vested, Weighted Average Grant Date Fair Value per Unit | $ / shares	16.13	[2]
Ending balance, Vested, Weighted Average Grant Date Fair Value per Unit | $ / shares	$ 15.51

[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.