Consolidated Statements of Changes In Shareholders' Equity (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) $ / shares shares
Statement of Stockholders' Equity [Abstract]
Cash dividends (in dollars per share) | $ / shares	$ 1.20
Stock issuance costs | $	$ 0
Class B Common Stock
Statement of Stockholders' Equity [Abstract]
Stock Repurchased and Retired During Period, Shares | shares	0