Stock Compensation Plan - Summary of Stock Options Outstanding (Details)	12 Months Ended
	Dec. 31, 2017 Employees $ / shares shares
Number of Shares	1,778,100
Stock Option Grant One [Member]
Date of Grant	Jul. 27, 2010
Number of Employees | Employees	4
Number of Shares	34,000
Option Price | $ / shares	$ 11.40
Expiration Date	Jul. 27, 2018
Stock Option Grant Two [Member]
Date of Grant	Jul. 05, 2011
Number of Employees | Employees	4
Number of Shares	34,000
Option Price | $ / shares	$ 11.16
Expiration Date	Jul. 05, 2019
Stock Option Grant Three [Member]
Date of Grant	Aug. 29, 2012
Number of Employees | Employees	6
Number of Shares	44,000
Option Price | $ / shares	$ 11.29
Expiration Date	Aug. 29, 2020
Stock Option Grant Four [Member]
Date of Grant	Jun. 26, 2013
Number of Employees | Employees	10
Number of Shares	232,100
Option Price | $ / shares	$ 10.08
Expiration Date	Jun. 26, 2021
Stock Option Grant Five [Member]
Date of Grant	Jun. 11, 2014
Number of Employees | Employees	11
Number of Shares	175,000
Option Price | $ / shares	$ 9.85
Expiration Date	Jun. 11, 2022
Stock Option Grant Six [Member]
Date of Grant	Jun. 24, 2015
Number of Employees | Employees	12
Number of Shares	303,000
Option Price | $ / shares	$ 9.82
Expiration Date	Jun. 24, 2023
Stock Option Grant Seven [Member]
Date of Grant	Apr. 05, 2016
Number of Employees | Employees	21
Number of Shares	380,000
Option Price | $ / shares	$ 9.77
Expiration Date	Apr. 05, 2024
Stock Option Grant Eight [Member]
Date of Grant	Jan. 19, 2017
Number of Employees | Employees	2
Number of Shares	60,000	[1]
Option Price | $ / shares	$ 14.25
Expiration Date	Jan. 19, 2027
Stock Option Grant Nine [Member]
Date of Grant	Apr. 04, 2017
Number of Employees | Employees	34
Number of Shares	516,000	[1]
Option Price | $ / shares	$ 15.04
Expiration Date	Apr. 04, 2027

[1] Unexercisable