Stockholder's Equity (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	Dec. 31, 2010
Accumulated other comprehensive income (loss)
Warrants issued (in shares)					1,481,055
Exercise Price (in dollars per share)					$ 14.00
Shares of common stock issued on exercise of warrants				21,371
Warrants exercised				238,697
Warrants exercised value				$ 3,300
Components of accumulated other comprehensive income (loss)
Balance at the beginning of the period	$ (29,235)	$ (25,184)	$ (29,388)	(23,947)
Other comprehensive income (loss), net of tax	153	2,520	306	1,283
Balance at the end of the period	(29,082)	(22,664)	(29,082)	(22,664)
Unrealized Gain (Loss) on Investments
Components of accumulated other comprehensive income (loss)
Balance at the beginning of the period		(62)		(64)
Other comprehensive income (loss), net of tax		(2)
Balance at the end of the period		(64)		(64)
Retirement plans
Components of accumulated other comprehensive income (loss)
Balance at the beginning of the period	(29,235)	(25,122)	(29,388)	(23,883)
Other comprehensive income (loss), net of tax	153	2,522	306	1,283
Balance at the end of the period	$ (29,082)	$ (22,600)	$ (29,082)	$ (22,600)