Stock Options - Number & Weighted Average Exercise Price (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Number of Options
Outstanding at beginning of year (in shares)	3,076	3,045
Granted at price = market value (in shares)	43	224
Granted at price > market value (in shares)		75
Exercised (in shares)	(150)	(193)
Forfeited (in shares)	(10)	(40)
Expired (in shares)	(361)	(33)
Outstanding at end of year (in shares)	2,598	3,076
Options exercisable at end of year (in shares)	2,287	2,511
Weighted Average Exercise Price
Outstanding at beginning of year (in dollars per share)	$ 0.86	$ 0.74
Granted at price = market value (in dollars per share)	2.13	1.83
Granted at price > market value (in dollars per share)		1.98
Exercised (in dollars per share)	0.44	0.40
Forfeited (in dollars per share)	1.36	1.28
Expired (in dollars per share)	2.77	1.90
Outstanding at end of year (in dollars per share)	0.63	0.86
Options exercisable at end of year (in dollars per share)	$ 0.51	$ 0.78