Common Stock - Stock Repurchase Program (Details) - USD ($)	3 Months Ended		9 Months Ended		16 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Jun. 30, 2015	Nov. 30, 2012
Equity, Class of Treasury Stock [Line Items]
Repurchase of common stock			$ 925,000
Stock repurchase program, remaining amount	$ 54,900,000		54,900,000		$ 54,900,000
Credit Facility
Equity, Class of Treasury Stock [Line Items]
Share repurchase covenant			$ 4,900,000
Share Repurchase Program, November 2012
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, authorized amount (up to)							$ 25,000,000
Repurchase of common stock during period (in shares)	0	2,404	0	549,723
Repurchase of common stock (in dollars per share)		$ 16.44		$ 13.28
Repurchase of common stock				$ 7,300,000
Share Repurchase Program, June 2015
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, authorized amount (up to)						$ 50,000,000
Repurchase of common stock during period (in shares)					0