Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Consolidated Statements of Stockholders' Equity [Abstract]
Issuance of stock and related tax withholdings for vested restricted stock units (in shares)	212,392	230,624	211,328
Conversion of Class B shares(in shares)	261	18	31,800
Dividends declared (in dollars per share)	$ 0.38	$ 0.37	$ 0.3225

Number of shares issued during the period related to Restricted Stock Awards, net of any shares forfeited.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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