Stock-Based Compensation - Restricted Shares (Details) - Restricted stock - Class A Non-Voting - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based award vesting period	5 years
Shares
Nonvested at the beginning of the period (in shares)	72,109	112,219	67,669
Granted (in shares)	149,496	112,502	210,875
Vested (in shares)	(108,610)	(131,260)	(166,325)
Forfeited or unearned (in shares)	(31,387)	(21,352)	0
Nonvested at the end of the period (in shares)	81,608	72,109	112,219
Weighted-Average Grant-Date Fair Value
Nonvested at the beginning of the period, weighted-average grant-date fair value (in usd per share)	$ 7.76	$ 7.89	$ 7.56
Granted, weighted-average grant-date fair value (in usd per share)	9.38	7.81	9.26
Vested, weighted-average grant-date fair value (in usd per share)	9.04	8.27	9.50
Forfeited or unearned, weighted-average grant-date fair value (in usd per share)	9.55	8.43	0.00
Nonvested at the end of the period, weighted-average grant-date fair value (in usd per share)	$ 8.35	$ 7.76	$ 7.89
Share-based compensation expense	$ 1,205	$ 1,176	$ 1,205
Unearned compensation cost	$ 358

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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