Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2015

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock-based compensation assumptions used in the option valuation models

The assumptions used in the option valuation models are outlined in the following table:

	Year Ended December 31,
	2014			2013
Weighted average grant date fair value per share	$	106.08		$	113.31
Weighted average assumptions used:
Expected volatility	45		%	45		%
Expected life (in years)	6.25			6.11
Risk-free interest rate	1.98		%	0.95		%
Expected dividend yield	—		%	—		%

Stock option activity

The following table summarizes stock option activity during the years ended December 31, 2015, 2014 and 2013 (shares in thousands):

	Year Ended			Year Ended			Year Ended
	December 31, 2015			December 31, 2014			December 31, 2013
	Options	Weighted Average Exercise Price		Options	Weighted Average Exercise Price		Options		Weighted Average Exercise Price
Outstanding at beginning of period	130	$	218.46	129	$	218.38	129		$	216.62
Granted	—	$	—	1	$	229.84	4		$	258.37
Exercised (1)	—	$	—	—	$	—	(3	)	$	193.13
Forfeited	—	$	—	—	$	—	(1	)	$	258.37
Outstanding at end of period (2)	130	$	218.46	130	$	218.46	129		$	218.38
Options exercisable at end of period (3)	93	$	202.48	88	$	199.50	82		$	196.33
Available for grant at end of period	10			10			11

(1) The total intrinsic value of the options exercised during the year ended December 31, 2013 was $0.2 million.

(2) Stock options outstanding at December 31, 2015 have a weighted average remaining contractual term of 3.4 years and the aggregate intrinsic value is zero.

(3) Exercisable stock options at December 31, 2015 have a weighted average remaining contractual term of 2.2 years and there is no intrinsic value.