Shareholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				12 Months Ended
	Jun. 30, 2014	Sep. 30, 2013	Jun. 30, 2013	Sep. 30, 2012	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Feb. 28, 2013
Equity Components [Line Items]
Stock repurchased during period, shares						585,000
Stock repurchased during period, aggregate purchase price						$ 5,588	$ 1,523
Amount of stock repurchase plan authorized								$ 15,000
Quarterly cash dividend per share of common stock outstanding approved	$ 0.03	$ 0.025	$ 0.0275	$ 0.025	$ 0.120	$ 0.118	$ 0.108
Dividend payment from cash on hand					$ 3,408	$ 3,295	$ 2,967
Price of Rights per unit					$ 33.33
Treasury Stock [Member]
Equity Components [Line Items]
Stock repurchased during period, shares						585,000	253,000
Stock repurchased during period, aggregate purchase price						$ 5,588	$ 1,523