Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Earnings Per Share [Abstract]
Net income	$ 21,767	$ 17,341	$ 43,786	$ 35,163
Weighted average shares outstanding - basic and diluted (in shares)	5,113,844	5,112,026	5,113,461	5,111,616
Net income per common share- basic and diluted (in dollars per share)	$ 4.26	$ 3.39	$ 8.56	$ 6.88