Share-Based Compensation - Summary of Liability Based Award Activity (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Restricted Stock (RSU)
Summary of Liability-Based Award Activity [Roll Forward]
Granted, Weighted-Average Grant Date Fair Value	$ 27.35
Liability Based Awards | Performance unit incentive plan (PUP)
Summary of Liability-Based Award Activity [Roll Forward]
Beginning Balance, Shares	210,600	95,500	102,960
Granted, Shares	93,100	115,100	95,500
Vested, Shares	0	0	0
Forfeited or Cancelled, Shares	(3,932)	0	(102,960)
Ending Balance, Shares	299,768	210,600	95,500
Beginning Balance, Weighted-Average Grant Date Fair Value	$ 21.70	$ 23.02	$ 33.81
Granted, Weighted-Average Grant Date Fair Value	$ 27.35	$ 20.60	$ 23.02
Vested, Weighted-Average Grant Date Fair Value	$ 0.00	$ 0.00	$ 0.00
Forfeited or Cancelled, Weighted-Average Grant Date Fair Value	$ 21.15	$ 0.00	$ 33.81
Ending Balance, Weighted-Average Grant Date Fair Value	$ 23.46	$ 21.70	$ 23.02
Liability Based Awards | Restricted Stock (RSU)
Summary of Liability-Based Award Activity [Roll Forward]
Beginning Balance, Shares	40,500	38,600	26,050
Granted, Shares	8,600	15,850	12,550
Vested, Shares	(11,300)	(13,100)	0
Forfeited or Cancelled, Shares	(9,240)	(850)	0
Ending Balance, Shares	28,560	40,500	38,600
Beginning Balance, Weighted-Average Grant Date Fair Value	$ 20.82	$ 19.07	$ 17.18
Granted, Weighted-Average Grant Date Fair Value		$ 20.57	$ 23.01
Vested, Weighted-Average Grant Date Fair Value	$ 19.10	$ 15.36	$ 0.00
Forfeited or Cancelled, Weighted-Average Grant Date Fair Value	$ 22.55	$ 20.89	$ 0.00
Ending Balance, Weighted-Average Grant Date Fair Value	$ 22.91	$ 20.82	$ 19.07
Liability Based Awards | Performance Based Restricted Stock Shares (PBRSU)
Summary of Liability-Based Award Activity [Roll Forward]
Beginning Balance, Shares	0	1,956	3,914
Granted, Shares	0	0	0
Vested, Shares	0	(1,956)	(1,958)
Forfeited or Cancelled, Shares	0	0	0
Ending Balance, Shares	0	0	1,956
Beginning Balance, Weighted-Average Grant Date Fair Value	$ 0.00	$ 15.36	$ 15.36
Granted, Weighted-Average Grant Date Fair Value	$ 0.00	$ 0.00	$ 0.00
Vested, Weighted-Average Grant Date Fair Value	$ 0.00	$ 15.36	$ 15.36
Forfeited or Cancelled, Weighted-Average Grant Date Fair Value	$ 0.00	$ 0.00	$ 0.00
Ending Balance, Weighted-Average Grant Date Fair Value	$ 0.00	$ 0.00	$ 15.36