Treasury Stock - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Apr. 01, 2016	Jul. 01, 2016
Equity Class Of Treasury Stock [Line Items]
Stock repurchase program, authorized amount		$ 10,000,000
Stock repurchase program, period		2 years
Treasury stock purchase, shares	384,000		0
Shares authorized to repurchase, remaining amount	$ 6,900,000
Issued treasury stock, shares	58,000		148,000
Remaining shares authorized for repurchase			500,000
Remaining shares from the trusts recorded as treasury stock	11,454,063	11,077,779
Shares released from employee stock trust			500,000
Stock Employee Compensation Trust (SECT) and Omnibus Stock Trust [Member]
Equity Class Of Treasury Stock [Line Items]
Remaining shares from the trusts recorded as treasury stock				2,800,000