Summary of Stock Option Activity (Details) - Stock Options	12 Months Ended
	Dec. 31, 2015 $ / shares shares
Changes in shares granted for stock options for the year
Options outstanding, Beginning Balance | shares	1,000
Options, Exercised | shares	(1,000)
Options, forfeited or expired | shares	0
Options outstanding, Ending Balance | shares	0
Options, Exercisable | shares	0
Weighted-Average Exercise Price
Options outstanding, Weighted Average Exercise Price, Beginning Balance | $ / shares	$ 16.73
Options, exercised, weighted average exercise price | $ / shares	16.73
Options, forfeited or expired, weighted average exercise price | $ / shares	0.00
Options outstanding, Weighted Average Exercise Price, Ending Balance | $ / shares	0.00
Options exercisable, Weighted Average Exercise Price | $ / shares	$ 0.00