Revenue Recognition - Contract Balances (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Receivables, which are included in accounts receivable - trade, net	$ 1,520,000				$ 2,129,000				$ 1,520,000	$ 2,129,000
Contract costs, net, which are included in other current assets	6,529,000				8,766,000				6,529,000	8,766,000
Payables, which are included in other current liabilities	1,113,000				1,663,000				1,113,000	1,663,000
Contract liabilities, which are included in other current liabilities	7,633,000				9,358,000				7,633,000	9,358,000
Contract costs, net, which are included in other assets	24,002,000				18,443,000				24,002,000	18,443,000
Contract liabilities, which are included in other liabilities	32,104,000				29,045,000				$ 32,104,000	29,045,000
Commercial leasing contracts, receivable and payable term expectation									12 months
Contract asset reclassified to receivable									$ (609,000)
Cash collections									$ 1,911,000
Development marketing project period, minimum									4 years
Development marketing project period, maximum									6 years
Contract liabilities estimated to be recognized over next twelve months	7,633,000								$ 7,633,000
Revenue recognized on contract liabilities									8,846,000	14,973,000	$ 12,135,000
Revenue recognized relating to performance obligations satisfied or partially satisfied in prior periods									0
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenues	$ 554,590,000	$ 547,831,000	$ 445,760,000	$ 454,488,000	$ 439,565,000	$ 504,790,000	$ 538,432,000	$ 420,924,000	2,002,669,000	1,903,711,000	1,870,262,000
Total cost of sales									1,367,145,000	$ 1,301,579,000	$ 1,292,484,000
Advance payments received from customer									24,821,000
Contract liabilities increase									1,334,000
Real Estate Commercial Leasing | Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total cost of sales									(550,000)
Additional expense accruals									1,398,000
Transferred over Time
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Advance payments received from customer									21,067,000
Contract liabilities increase									$ 3,322,000